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Search: id:A079164
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| A079164 |
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Twin-primorial numbers: products of twin primes. |
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+0
1
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| 3, 15, 75, 525, 5775, 75075, 1276275, 24249225, 703227525, 21800053275, 893802184275, 38433493923825, 2267576141505675, 138322144631846175, 9820872268861078425, 716923675626858725025, 72409291238312731227525
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The sum of the reciprocals converges to 0.4154254016622336549103692152614908366885449298862362851444631680740051..
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PROGRAM
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(PARI) twprfact(n) = {sr=0; tp = vector(10000); k=1; forprime(j = 3, n, if(nextprime(j+1)-j == 2, tp[k] = j; tp[k+1] = j+2; k+=2; ); ); for(j=1, k-1, y=1; for(i = 1, j, y*=tp[i]; ); print1(y", "); sr+=1.0/y; ); print(); print(sr); }
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CROSSREFS
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Adjacent sequences: A079161 A079162 A079163 this_sequence A079165 A079166 A079167
Sequence in context: A136778 A000266 A059838 this_sequence A047015 A037759 A037647
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Feb 03 2003
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