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A098169 a(n)= sum_{i=1 to n} A098168(i). 0
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 (list; graph; refs; listen; history; text; internal format)
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}] (from 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

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Last modified November 24 08:42 EST 2014. Contains 249873 sequences.