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.

Showing 1-9 of 9 results.

A185577 Decimal expansion of Sum'_{m,n,p = -infinity..infinity} (-1)^m/sqrt(m^2 + n^2 + p^2), negated.

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 31 2011

Keywords

Comments

The prime at the sum symbol means that the term at m=n=p=0 is omitted.

Examples

			0.77438614142400281521275138640678...
		

Crossrefs

Programs

  • Mathematica
    digits = 105; Clear[f]; f[n_, p_] := f[n, p] =(s = Sqrt[n^2 + p^2]; ((2 + (-1)^n)*Csch[s*Pi])/s // N[#, digits+10]&); f[m_] := f[m] = Pi/2 - (7*Log[2])/2 + 4*Sum[f[n, p], {n, 1, m}, {p, 1, m}] // RealDigits[#, 10, digits+10]& // First; f[0]; f[m=10]; While[f[m] != f[m-10], Print[m]; m = m+10]; f[m][[1 ;; digits]] (* Jean-François Alcover, Feb 20 2013 *)

Formula

sqrt(3)*(3*(this value) + A085469)/4 = A181152.
Equals Pi/2 - 7*log(2)/2 + 4*Sum_{n>=1, p>=1} (2+(-1)^n) *cosech(d*Pi)/d with d = sqrt(n^2 + p^2).

Extensions

More terms from Jean-François Alcover, Feb 20 2013

A185578 Decimal expansion of Sum'_{m,n,p = -infinity .. infinity} (-1)^(m + n)/sqrt(m^2 + n^2 + p^2), negated.

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 31 2011

Keywords

Comments

The prime at the sum symbol means the term at m=n=p=0 is omitted.

Examples

			1.48038980651222259790776170...
		

Crossrefs

Programs

  • Mathematica
    digits = 105; Clear[f]; f[n_, p_] := f[n, p] = (s = Sqrt[n^2 + p^2]; ((1 + (-1)^n + (-1)^(n + p))*Csch[s*Pi])/s // N[#, digits+10]&); f[m_] := f[m] = Pi/2 - 9*Log[2]/2 + 4*Sum[f[n, p], {n, 1, m}, {p, 1, m}] // RealDigits[#, 10, digits + 10]& // First; f[0]; f[m=10]; While[ f[m] != f[m-10], Print[m]; m = m+10]; f[m][[1 ;; digits]] (* Jean-François Alcover, Feb 20 2013 *)

Formula

Equals Pi/2 - 9*log(2)/2 + 4*Sum_{p>=1, n>=1} (1+(-1)^n+(-1)^(n+p))*cosech(d*Pi)/d where d = sqrt(n^2 + p^2).

Extensions

More terms from Jean-François Alcover, Feb 20 2013

A185579 Decimal expansion of Sum_{m,n,p = -infinity..infinity} (-1)^m/sqrt(m^2 + (n-1/2)^2 + (p-1/2)^2).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 31 2011

Keywords

Examples

			1.5401709018555436174364666638648...
		

Crossrefs

Programs

  • Mathematica
    digits = 105; Clear[f]; f[n_, p_] := f[n, p] = (d = Sqrt[n^2 + (p - 1/2)^2]; (-1)^n*(Csch[d*Pi]/d) // N[#, digits+10]&); f[m_] := f[m] = 2*Log[1 + Sqrt[2]] + 4*Sum[f[n, p], {n, 1, m}, {p, 1, m}] // RealDigits[#, 10, digits+10]& // First; f[0]; f[m = 10]; While[f[m] != f[m-10], Print[m]; m = m+10]; f[m][[1 ;; digits]] (* Jean-François Alcover, Feb 21 2013 *)

Formula

Equals 2*log(1+sqrt(2)) + 4*Sum_{n>=1, p>=1} (-1)^n*cosech(d*Pi)/d where d = sqrt(n^2 + (p-1/2)^2).

Extensions

More terms from Jean-François Alcover, Feb 21 2013

A185580 Decimal expansion of Sum_{m,n,p = -infinity..infinity} (-1)^(m+n)/sqrt( m^2 + n^2 + (p-1/2)^2 ).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 31 2011

Keywords

Crossrefs

Programs

  • Mathematica
    digits = 105; Clear[f]; f[n_, p_] := f[n, p] = (d = Sqrt[(n - 1/2)^2 + (p - 1/2)^2]; (Csch[d*Pi]/d) // N[#, digits + 10] &); f[m_] := f[m] = 4*Sum[f[n, p], {n, 1, m}, {p, 1, m}] // RealDigits[#, 10, digits + 10] & // First; f[0]; f[m = 10]; While[f[m] != f[m - 10], Print[m]; m = m + 10]; f[m][[1 ;; digits]] (* Jean-François Alcover, Feb 21 2013 *)

Formula

Equals 4*Sum_{n>=1, p>=1} cosech(d*Pi)/d where d = sqrt((n-1/2)^2 + (p-1/2)^2).

Extensions

More terms from Jean-François Alcover, Feb 21 2013

A185581 Decimal expansion of 8*Sum_{m,n,p = -infinity..infinity} (-1)^(m + n + p)/ sqrt( (2*m-1/2)^2+(2*n-1/2)^2+(2*p-1/2)^2 ).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 31 2011

Keywords

Comments

The formula for g(1) in the 1976 paper on page 503 is a factor 2 too large.

Examples

			2.533557404433121025294862795718...
		

Crossrefs

Programs

  • Mathematica
    digits = 105; Clear[f]; f[n_, p_] := f[n, p] = (d = Sqrt[(2 n - 1/2)^2/2 + (p - 1/2)^2]; (-1)^n*(Csch[d*Pi]/d) // N[#, digits + 10] &); f[m_] := f[m] = 2 Sqrt[2]*Sum[f[n, p], {n, -m, m}, {p, -m, m}] // RealDigits[#, 10, digits + 10] & // First; f[0]; f[m = 10]; While[ f[m] != f[m - 10], Print[m]; m = m + 10]; f[m][[1 ;; digits]] (* Jean-François Alcover, Feb 21 2013 *)

Formula

Equals 2*sqrt(2)*Sum_{n,p = -infinity..infinity} (-1)^n*cosech(d*Pi)/d where d = sqrt( (2*n-1/2)^2/2 + (p-1/2)^2 ).

Extensions

More terms from Jean-François Alcover, Feb 21 2013

A185582 Decimal expansion of Sum_{m,n,p = -infinity..infinity} 4*(-1)^(m+p)/sqrt(m^2 + (2n-1/2)^2 + (2p-1/2)^2).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 31 2011

Keywords

Comments

The defining equation (3.10i) on page 1738 of the 1975 paper has a typo (m for n).
The value in Table 4 (page 1742, column h(2s)) seems to have two digits swapped.

Examples

			3.634899011049148711368042992007815327990...
		

Crossrefs

Programs

  • Mathematica
    digits = 105; Clear[f]; f[n_, p_] := f[n, p] = (d = Sqrt[2 n^2 + (p - 1/2)^2]; (Csch[d*Pi]/d) // N[#, digits + 10] &); f[m_] := f[m] = 4 Log[1 + Sqrt[2]] + 8*Sum[f[n, p], {n, 1, m}, {p, 1, m}] // RealDigits[#, 10, digits + 10] & // First; f[0]; f[m = 10]; While[ f[m] != f[m - 10], Print[m]; m = m + 10]; f[m][[1 ;; digits]] (* Jean-François Alcover, Feb 21 2013 *)

Formula

Equals 4*log(1+sqrt(2)) + 8*Sum_{n>=1, p>=1} cosech(d*Pi)/d where d = sqrt(2*n^2 + (p-1/2)^2).

Extensions

More terms from Jean-François Alcover, Feb 21 2013

A185583 Decimal expansion of Sum_{m,n,p = -infinity..infinity} 4*(-1)^(m + n + p)/sqrt(m^2 + (2n-1/2)^2 + (2p-1/2)^2).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 31 2011

Keywords

Examples

			1.285846549754779458631385161116...
		

Crossrefs

Programs

  • Mathematica
    digits = 105; Clear[f]; f[n_, p_] := f[n, p] = (d = Sqrt[(n - 1/2)^2 + 2*(p - 1/2)^2]; (Csch[d*Pi]/d) // N[#, digits + 10] &); f[m_] := f[m] = 8*Sum[f[n, p], {n, 1, m}, {p, 1, m}] // RealDigits[#, 10, digits + 10] & // First; f[0]; f[m = 10]; While[ f[m] != f[m - 10], Print[m]; m = m + 10]; f[m][[1 ;; digits]] (* Jean-François Alcover, Feb 21 2013 *)

Formula

Equals 8*Sum_{n>=1, p>=1} cosech(d*Pi)/d where d = sqrt((n-1/2)^2 + 2*(p-1/2)^2).

Extensions

More terms from Jean-François Alcover, Feb 21 2013

A247046 Decimal expansion of delta_3, a constant associated with a certain 3-dimensional lattice sum.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Sep 10 2014

Keywords

Examples

			-2.313698703882320603588809874061155008356357135595965962...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Sections 1.10 Madelung's constant, p. 79.

Crossrefs

Programs

  • Mathematica
    digits = 100; k0 = 10; dk = 10; Clear[s]; s[k_] := s[k] = 7*(Pi/6) - 19/2*Log[2] + 4*Sum[(3 + 3*(-1)^m + (-1)^(m + n))*Csch[Pi*Sqrt[m^2 + n^2]]/Sqrt[m^2 + n^2], {m, 1, k}, {n, 1, k}] // N[#, digits + 10] &; s[k0]; s[k = k0 + dk]; While[RealDigits[s[k], 10, digits + 5][[1]] != RealDigits[s[k - dk], 10, digits + 5][[1]], Print["s(", k, ") = ", s[k]]; k = k + dk]; Pi0 = s[k]; delta3 = Pi0 + Pi/6; RealDigits[delta3, 10, digits] // First

Formula

Pi_0 + Pi/6, where Pi_0 is A185576.

A381701 Decimal expansion of the universal aspect ratio, also called the magic box length ratio, L_z/L_x = L_z/L_y, for which the finite-size error of the self-diffusion coefficient vanishes.

Original entry on oeis.org

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

Views

Author

Alex Eduardo Delhumeau, Mar 04 2025

Keywords

Comments

Derived by Kikugawa et al. (2015) for a rod-shaped rectangular box (box with lengths L_x = L_y <= L_z) with periodic boundary conditions. The self-diffusion coefficient in the x (and y) direction of a monoatomic Lennard-Jones fluid, calculated from molecular dynamics simulation using the Einstein-Helfand formula, D_xx ( = D_yy), becomes system-size independent and represents the true self-diffusion coefficient, D_0.
Based on the expression for the finite-size correction to the self-diffusion coefficient derived from hydrodynamic theory by B. Dünweg and K. Kremer (1993) and greatly popularized by I.-C. Yeh and G. Hummer (2004). Computed to nine decimal places by J. Busch and D. Paschek (2023).

Examples

			2.793359649...
		

Crossrefs

Cf. A185576.
Showing 1-9 of 9 results.