Search: id:A087281 Results 1-1 of 1 results found. %I A087281 %S A087281 2,29,843,24476,710647,20633239,599074578,17393796001,505019158607, %T A087281 14662949395604,425730551631123,12360848946698171,358890350005878082, %U A087281 10420180999117162549,302544139324403592003,8784200221406821330636 %N A087281 Lucas numbers L(7n). %C A087281 a(n+1)/a(n) converges to (29+sqrt(845))/2 = 29.0344418537... a(0)/a(1)=2/ 29; a(1)/a(2)=29/843; a(2)/a(3)=843/24476; a(3)/a(4)=24476/710647; ... etc. Lim a(n)/a(n+1) as n approaches infinity = 0.0344418537... = 2/(29+sqrt(845)) = (sqrt(845)-29)/2. %H A087281 Tanya Khovanova, Recursive Sequences %H A087281 Index entries for recurrences a(n) = k*a(n - 1) +/- a(n - 2) %F A087281 a(n) =29a(n-1) + a(n-2), starting with a(0) = 2 and a(1) = 29, a(n) = ((29+sqrt(845))/2)^n + ((29-sqrt(845))/2)^n, (a(n))^2 =a(2n)-2 if n=1, 3, 5..., (a(n))^2 =a(2n)+2 if n=2, 4, 6.... %F A087281 G.f.: (2-29*x)/(1-29*x-x^2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 02 2008] %e A087281 a(4) = 710647 = 29a(3) + a(2) = 29*24476+ 843=((29+sqrt(845))/2)^4 + ( (29-sqrt(845))/2)^4 =710646.9999985928 + 0.0000014071 = 710647. %Y A087281 Cf. A000032. %Y A087281 Sequence in context: A013517 A006988 A090251 this_sequence A024234 A077282 A059725 %Y A087281 Adjacent sequences: A087278 A087279 A087280 this_sequence A087282 A087283 A087284 %K A087281 easy,nonn %O A087281 0,1 %A A087281 Nikolay V. Kosinov (kosinov(AT)unitron.com.ua), Oct 19 2003 %E A087281 More terms from Ray Chandler (rayjchandler(AT)sbcglobal.net), Feb 14 2004 Search completed in 0.001 seconds