a(1) = 3 because 3^3-2 = 25 = 5*5
a(2) = 8 because 3^8-2 = 6559 = 7*937
a(3) = 10 because 3^10-2 = 59047 = 137*431
a(4) = 12 because 3^12-2 = 531439 = 113*4703
a(5) = 13 because 3^13-2 = 1594321 = 197*8093
a(6) = 15 because 3^15-2 = 14348905 = 5*2869781
a(7) = 16 because 3^16-2 = 43046719 = 89*483671
a(8) = 19 because 3^19-2 = 1162261465 = 5*232452293
a(9) = 20 because 3^20-2 = 3486784399 = 7*498112057
a(10) = 21 because 3^21-2 = 10460353201 = 3719*2812679
a(11) = 25 because 3^25-2 = 847288609441 = 19*44594137339
a(12) = 28 because 3^28-2 = 22876792454959 = 4273*5353801183
a(13) = 39 because 3^39-2 = 4052555153018976265 = 5*810511030603795253
a(14) = 42 because 3^42-2 = 109418989131512359207 = 1559*70185368269090673
a(15) = 44 because 3^44-2 = 984770902183611232879 = 7*140681557454801604697
a(16) = 48 because 3^48-2 = 79766443076872509863359 = 257*310375264890554513087
a(17) = 55 because 3^55-2 = 174449211009120179071170505 = 5*34889842201824035814234101
a(18) = 57 because 3^57-2 = 1570042899082081611640534561 = 10199415869*153934589906668469
a(19) = 60 because 3^60-2 = 42391158275216203514294433199 = 32297*1312541668737536102866967
a(20) = 66 because 3^66-2 = 30903154382632612361920641803527 = 1423*21716903993417155560028560649
a(21) = 67 because 3^67-2 = 92709463147897837085761925410585 = 5*18541892629579567417152385082117
a(22) = 76 because 3^76-2 = 1824800363140073127359051977856583919 = 304489*5992992729261395739613095966871
a(23) = 78 because 3^78-2 = 16423203268260658146231467800709255287 = 17*966070780485921067425380458865250311
a(24) = 85 because 3^85-2 = 35917545547686059365808220080151141317041 = 20834335891*1723959224599124006021249572651
a(25) = 118 because 3^118-2 = 199667811101603467823686647723289448859052847504205678487 = 1435937*139050537106853203046990674189250258792031159796151
a(26) = 130 because 3^130-2 = 106111661199647248543687855752712667991103904330482569981872647 = 1549709916577*68471950824207627331281820863410579966190265823911
a(27) = 156 because 3^156-2 = 269721605590607563262106870407286853611938890184108047911269431464974473519 = 341652193*789462532706785708418113008884701798509863187631018800196225965583
a(28) = 162 because 3^162-2 = 196627050475552913618075908526912116283103450944214766927315415537966391196807 = 1801*109176596599418608338742869809501452683566602412112585745316721564667624207
a(29) = 193 because 3^193-2 = 121451298068529844233553416568714964256622520646270917226600348303197298080156462274524325121 = 436999744065129499999522339*277920753313825750274886555245065259531344474683466016812212480139
a(30) = 212 because 3^212-2 = 141158163862183763292171284564016760661754655311572624335224092241585052457078933432718798844642935439 = 7*20165451980311966184595897794859537237393522187367517762174870320226436065296990490388399834948990777
a(31) = 214 because 3^214-2 = 1270423474759653869629541561076150845955791897804153619017016830174265472113710400894469189601786418967 = 647*1963560239195755594481517095944591724815752546837949952112854451583099647780077899373213585165048561
a(32) = 217 because 3^217-2 = 34301433818510654479997622149056072840806381240712147713459454414705167747070180824150668119248233312161 = 1008657224142168957631832069522174813*34007027360244148559267660395710064330686087684754384784587116498197
a(33) = 218 because 3^218-2 = 102904301455531963439992866447168218522419143722136443140378363244115503241210542472452004357744699936487 = 7*14700614493647423348570409492452602646059877674590920448625480463445071891601506067493143479677814276641
a(34) = 228 because 3^228-2 = 6076396096647706909168138770838836135530328017648434830996201971201776350890241322455818405320466786549738959 = 1196329*5079201537911148947461892816139068881160891374904758499540011126706596890061380542021315545573556092471
a(35) = 244 because 3^244-2 = 261568927457882874608733211757582315090892217214195250256575658313972901281170319830426649720495049350373165676996879 = 6714775477434204743301241*38954232846193609510505297414132853440826368634177010808306672471293974046108203869340261319
a(36) = 312 because 3^312-2 = 72749744522375265125206295317964396725533432866824952575839903695438498229007286764085775359585486700313225701595838552106856020213734128131130137439 = 3533965541664813954808601214194088447382516178959*20585866971442971829123879706326533360740082778124287625716320472151328619868196665493506933726412721
a(37) = 330 because 3^330-2 = 28184741597483696656312069157964177063996161347113995004333705075399690053307637022705338727754760094738346354479627852222290139603798760436551093970029428647 = 17041328692407729059417*1653905168206783829207429855418622666424320737263974965850387963430221282033921742424981561116645153794483733891965921766132010807240191
a(38) = 352 because 3^352-2 = 884467056134897769177403028352204277531894146980966017349124212298943513062971345024451521058208349266478534208013045806724329989399740544099720742247653959918481338239 = 6566747441*134688757879229326855027289049687738330653144268072059899573684898618520368182886085880689051188431302801878871286569068268865982324253140726159494497247554479
a(39) = 357 because 3^357-2 = 214925494640780157910108935889585639440250277716374742215837183588643273674302036840941719617144628871754283812547170131034012187424136952216232140366179912260190965192561 = 84389233*2546835502590480445652455875379097703616411322477296863402434094745751198785063455203363675756415855465285290749676207283860634062453642068487956755883536851913217
a(40) = 376 because 3^376-2 = 249799620696893784357094865956838755317958346625791117809525755630884855800376765539840968703725194703655688767505426963194173231851456365291746868674546182009460836904854209869919 = 59468009921711*4200571383265596366543543997809347771389262467334707973491843903429555203814171903368696427651725176747659811214516273932277838147527654549455066946024155140667157329
a(41) = 386 because 3^386-2 = 14750417802530881072502094739885371662770122409906339715534686344248119850156447628362069360986269022056164766032427956749652735167596646914112360848363277501476652958394736238608965127 = 7*2107202543218697296071727819983624523252874629986619959362098049178302835736635375480295622998038431722309252290346850964236105023942378130587480121194753928782378994056390891229852161
a(42) = 388 because 3^388-2 = 132753760222777929652518852658968344964931101689157057439812177098233078651408028655258624248876421198505482894291851610746874616508369822227011247635269497513289876625552626147480686159 = 890034808577*149155694747519463062617796484918909365995145422422466123453470760213712925668763616655931553258924556886637432463497328989223821099800938855445421990369492408488679586399567