This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A097589 #12 Mar 28 2015 22:46:55 %S A097589 3,8,15,28,51,68,87,110,147,208,275,336,407,454,561,620,681,790,879, %T A097589 982,1061,1212,1409,1510,1613,1846,2069,2196,2419,2610,2773,3002,3645, %U A097589 3884,4041,4208,4647,4886,5085,5276,5475,5858,6091,6842,7155,7928,8535,8848 %N A097589 a(n) = Sum_{i=1..n} A005235(i). %C A097589 The primes and fortunate numbers in the partial sum of the fortunate numbers (A005235): primes begin: 3, 1061, 1409, 1613, 2069, 6091; fortunate numbers in partial sum begin: 3, 1061, 1409, 1613, 6091, and these subsequences are not disjoint. [_Jonathan Vos Post_, Jan 27 2010] %F A097589 Let F(n) := a(n)/A007504(n). Conjecture: as n tends to infinity F(n) tends to Pi/2 with Pi=3.14159...... %t A097589 NextPrime[ n_Integer] := Block[{k}, k = n + 1; While[ !PrimeQ[ k ], k++ ]; k ]; Fortunate[ n_Integer] := Block[{p = Product[ Prime[i], {i, 1, n} ] + 1, q}, q = NextPrime[p]; q - p + 1 ]; t = Table[ Fortunate[ n ], {n, 1, 48}]; Table[Plus @@ Take[t, n], {n, 48}] (* _Robert G. Wilson v_, Sep 04 2004 *) %t A097589 Accumulate[NextPrime[#]-#+1&/@(Rest[FoldList[Times,1,Prime[Range[ 60]]]]+ 1)] (* _Harvey P. Dale_, May 27 2014 *) %Y A097589 Cf. A005235 A007504. %K A097589 nonn %O A097589 1,1 %A A097589 _Pierre CAMI_, Aug 29 2004 %E A097589 More terms from _Robert G. Wilson v_, Sep 04 2004