A098169 a(n) = Sum_{i=1..n} A098168(i).

2, 5, 9, 15, 24, 31, 39, 48, 60, 78, 97, 115, 135, 150, 178, 195, 213, 242, 266, 293, 315, 351, 396, 422, 449, 500, 548, 579, 627, 670, 708, 758, 875, 927, 964, 1003, 1088, 1140, 1186, 1229, 1275, 1351, 1402, 1535, 1600, 1737, 1848, 1913, 1989, 2051, 2137, 2204

Offset

1,1

Links

Table of n, a(n) for n=1..52.

Formula

Conjecture: a(n)/triangular(n) -> Log(e*Pi/2).

Mathematica

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[ PrimePi[ Fortunate[n]], {n, 70}]; Table[Plus @@ Take[t, n], {n, 52}] (* Robert G. Wilson v, Sep 04 2004 *)

Crossrefs

Cf. A005235, A055211, A098166, A098167, A098168.

Sequence in context: A047809 A014126 A019450 * A055610 A134342 A100287

Adjacent sequences: A098166 A098167 A098168 * A098170 A098171 A098172

Keyword

nonn

Author

Pierre CAMI, Aug 30 2004

Extensions

More terms from Robert G. Wilson v, Sep 04 2004

Status

approved