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.

A242013 Decimal expansion of the Euler-Kronecker constant (as named by P. Moree) for hypotenuse numbers.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Aug 11 2014

Keywords

Comments

130000 digits are available (see Links). - Alessandro Languasco, Mar 27 2024

Examples

			-0.1638973186345815958562997690047351186096657461435450436468425985305...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.3 Landau-Ramanujan constants, p. 99.

Crossrefs

Cf. A227158.

Programs

  • Mathematica
    digits = 101; m0 = 5; dm = 5; beta[x_] := 1/4^x*(Zeta[x, 1/4] - Zeta[x, 3/4]); L = Pi^(3/2)/Gamma[3/4]^2*2^(1/2)/2; Clear[f]; f[m_] := f[m] = 1/2*(1 - Log[Pi*E^EulerGamma/(2*L)]) - 1/4*NSum[Zeta'[2^k]/Zeta[2^k] - beta'[2^k]/beta[2^k] + Log[2]/(2^(2^k) - 1), {k, 1, m}, WorkingPrecision -> digits + 10]; f[m0]; f[m = m0 + dm]; While[RealDigits[f[m], 10, digits] != RealDigits[f[m - dm], 10, digits], m = m + dm]; RealDigits[1 - 2*f[m], 10, digits] // First

Formula

1 - 2*A227158.