cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A080729 Decimal expansion of the infinite product of zeta functions for even arguments.

Original entry on oeis.org

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

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Author

Deepak R. N (deepak_rn(AT)safe-mail.net), Mar 08 2003

Keywords

Comments

By elementary estimates, the constant lies in the open interval (Pi/6, exp(3/4)). - Bernd C. Kellner, May 18 2024

Examples

			1.82101745149929239040672513222600684857...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Product[Zeta[2n],{n,500}],10,110][[1]] (* Harvey P. Dale, Jan 31 2012 *)
  • PARI
    prodinf(k=1, zeta(2*k)) \\ Vaclav Kotesovec, Jan 29 2024

Formula

Decimal expansion of zeta(2)*zeta(4)*...*zeta(2k)*...
If u(k) denotes the number of Abelian groups with group order k (A000688), then Product_{k>=1} zeta(2*k) = Sum_{k>=1} u(k)/k^2. - Benoit Cloitre, Jun 25 2003
Equals A021002/A080730. - Amiram Eldar, Jan 31 2024
This constant C is connected with the product of values of the Dedekind eta function on the upper imaginary axis. The product runs over the primes, where i is the imaginary unit: 1/C = Product_{prime p} (p^(1/12) * eta(i * log(p) / Pi)). - Bernd C. Kellner, May 18 2024

Extensions

More terms from Benoit Cloitre, Mar 08 2003