A097590 a(n) = Sum_{i=2..n} A055211(i).

3, 10, 21, 34, 51, 80, 103, 146, 187, 260, 319, 366, 455, 522, 595, 702, 791, 892, 1019, 1116, 1199, 1288, 1385, 1636, 1767, 1880, 2031, 2294, 2545, 2768, 2947, 3336, 3617, 3768, 3965, 4138, 4377, 4610, 4801, 5024, 5247, 5540, 6133, 6426, 6883, 7110, 7421

Offset: 2

Author

Pierre CAMI, Aug 29 2004

Keywords

• nonn

Crossrefs

Cf. A007504, A055211.

Programs

Mathematica

PrevPrime[ n_Integer] := Block[ {k = n - 1}, While[ ! PrimeQ[ k ], k-- ]; k ]; LF[ n_Integer ] := Block[ { p = Product[ Prime[ i ], {i, 1, n} ] - 1, q}, q = PrevPrime[ p ]; p - q + 1 ]; t = Table[LF[ n ], {n, 2, 48}]; Table[Plus @@ Take[t, n], {n, 47}] (* Robert G. Wilson v, Sep 04 2004 *)

Formula

Let F(n) := a(n)/A007504(n). Conjecture: as n tends to infinity F(n) tends to Pi/2 with Pi=3.14159......

Extensions

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