A097909 Decimal expansion of Sum_{i >= 1} t(i)/g(i), where t(i) = triangular number(i) and g(i) = (sum of first i primes)^4.

0, 6, 8, 0, 5, 5, 9, 4, 0, 8, 1, 5, 2, 5, 7, 5, 6, 9, 3, 2, 6, 3, 1, 3, 6, 5, 1, 5, 1, 0, 0

Offset

0,2

Links

Table of n, a(n) for n=0..30.

Formula

Equals Sum_{n>=1} A000217(n)/A007504(n)^4. - R. J. Mathar, Dec 07 2014

Example

0.0680559408152575...

Mathematica

p = s = 0; Do[p += Prime[n]; k = n*(n+1)/2; s += k/p^4; Print[N[s, 50]], {n, 10^6}] (* Ryan Propper, Jul 22 2006 *)

Crossrefs

Cf. A000217, A007504.

Sequence in context: A200116 A360500 A308314 * A143819 A021599 A072553

Adjacent sequences: A097906 A097907 A097908 * A097910 A097911 A097912

Keyword

cons,more,nonn

Author

Pierre CAMI, Sep 04 2004

Extensions

Corrected and extended by Ryan Propper, Jul 22 2006

Offset corrected by R. J. Mathar, Jan 31 2009

Unproven and apparently incorrect term a(31) deleted by Jon E. Schoenfield, Oct 30 2022

Status

approved