A097907 - OEIS

A097907

Decimal expansion of Sum_{i >= 1} t(i)/g(i), where t(i) = triangular number(i) and g(i) = (sum of first i primes)^2.

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

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OFFSET

0,1

LINKS

Table of n, a(n) for n=0..11.

FORMULA

Equals Sum_{n>=1} A000217(n)/A007504(n)^2. - R. J. Mathar, Dec 07 2014

EXAMPLE

0.53699391743...

MATHEMATICA

Module[{nn=10^6}, RealDigits[Total[Accumulate[Range[nn]]/Accumulate[Prime[Range[nn]]]^2], 10, 30][[1]]] (* Gives the first 7 terms correctly. To generate more, increase the value of nn. *) (* Harvey P. Dale, May 27 2023 *)

CROSSREFS

Cf. A000217, A007504.

Sequence in context: A363229 A237656 A371847 * A198749 A338294 A066253

Adjacent sequences: A097904 A097905 A097906 * A097908 A097909 A097910

KEYWORD

nonn,cons,more

AUTHOR

Pierre CAMI, Sep 04 2004

EXTENSIONS

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

a(8)-a(11) from Jinyuan Wang, Jul 02 2022

STATUS

approved