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.

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A386718 Decimal expansion of Integral_{x=0..1} Integral_{y=0..1} Integral_{z=0..1} {1/(x*y*z)} dx dy dz, where {} denotes fractional part.

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Jul 31 2025

Keywords

Examples

			0.50044536217858002349633947881010515277510990544508...
		

References

  • Ovidiu Furdui, Limits, Series, and Fractional Part Integrals: Problems in Mathematical Analysis, New York: Springer, 2013. See section 2.43, page 106.

Crossrefs

Cf. A001620 (gamma), A082633 (-gamma_1), A086279 (-gamma_2).
Cf. A153810 (m=1), A242610 (m=2), this constant (m=3).

Programs

  • Mathematica
    With[{m = 2}, RealDigits[1 - Sum[StieltjesGamma[k]/k!, {k, 0, 2}], 10, 120][[1]]]

Formula

Equals 1 - gamma - gamma_1 - gamma_2/2, where gamma_k is the k-th Stieltjes constant.
In general, for m >= 1, Integral_{x_1=0..1} ... Integral_{x_m=0..1} {1/(x_1*...*x_m)} dx_1 ... dx_m = 1 - Sum_{k=0..m-1} gamma_k/k!, where gamma_0 = gamma is Euler's constant.

A386738 Decimal expansion of Integral_{x=0..1} {1/x}^4 dx, where {} denotes fractional part.

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Aug 01 2025

Keywords

Examples

			0.14553289487913287197745596494722440166566646379514...
		

Crossrefs

Cf. A153810 (m=1), A345208 (m=2), A345208 (m=3), this constant (m=4).

Programs

  • Mathematica
    RealDigits[Log[2*Pi] - 2*EulerGamma - 1/3 + (Zeta[3]/2 + Zeta'[2])/Zeta[2], 10, 120][[1]]
  • PARI
    log(2*Pi) - 2*Euler - 1/3 + (zeta(3)/2 + zeta'(2))/zeta(2)

Formula

Equals log(2*Pi) - 2*gamma - 1/3 + 3*zeta(3)/Pi^2 + 6*zeta'(2)/Pi^2.
In general, for m >= 2, Integral_{x=0..1} {1/x}^m dx = log(2*Pi) - m*gamma/2 - 1/(m-1) - Sum_{k=1..floor((m-2)/2)} (-1)^k * (m!/(m-2*k-1)!) * zeta(2*k+1) / (2^(2*k+1) * Pi^(2*k)) + 2 * Sum_{k=1..floor((m-1)/2)} (-1)^(k-1) * (m!/(m-2*k)!) * zeta'(2*k) / (2*Pi)^(2*k).
Previous Showing 11-12 of 12 results.