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 1-10 of 15 results. Next

A236923 Number of integer solutions to a^2 + b^2 + c^2 + 4*d^2 = n.

Original entry on oeis.org

1, 6, 12, 8, 8, 36, 48, 16, 24, 78, 72, 24, 32, 84, 96, 48, 24, 108, 156, 40, 48, 192, 144, 48, 96, 186, 168, 80, 64, 180, 288, 64, 24, 288, 216, 96, 104, 228, 240, 112, 144, 252, 384, 88, 96, 468, 288, 96, 96, 342, 372, 144, 112, 324, 480, 144, 192, 480, 360, 120, 192, 372, 384, 208, 24, 504, 576, 136, 144, 576, 576, 144, 312, 444, 456, 248, 160, 576, 672
Offset: 0

Views

Author

N. J. A. Sloane, Feb 14 2014

Keywords

Crossrefs

For number of solutions to a^2+b^2+c^2+k*d^2=n for k=1,2,3,4,5,6,7,8,12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

  • Maple
    with(numtheory);
    s:=n-> if whattype(n) = integer then sigma(n) else 0; fi;
    f:=proc(n) global s;
      if (n mod 4) = 0 then 8*s(n/4)-32*s(n/16)
    elif (n mod 4) = 2 then 12*s(n/2)
    elif (n mod 4) = 3 then 2*s(n)
    else 6*s(n);
    fi; end;
    [seq(f(n),n=1..100)];
    # a(0)=1 must be added separately
  • Mathematica
    EllipticTheta[3, 0, q]^3*EllipticTheta[3, 0, q^4] + O[q]^80 // CoefficientList[#, q]& (* Jean-François Alcover, Mar 04 2023, after Ilya Gutkovskiy *)

Formula

See Maple code.
G.f.: theta_3(q)^3*theta_3(q^4), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018

A236928 Number of integer solutions to a^2 + b^2 + c^2 + 2*d^2 = n.

Original entry on oeis.org

1, 6, 14, 20, 30, 40, 36, 48, 62, 42, 72, 100, 68, 120, 112, 48, 126, 108, 98, 180, 136, 160, 180, 144, 132, 126, 216, 200, 240, 280, 112, 192, 254, 120, 252, 320, 210, 360, 324, 144, 264, 252, 288, 420, 340, 280, 336, 288, 260, 342, 294, 360, 408, 520, 360, 240, 496
Offset: 0

Views

Author

N. J. A. Sloane, Feb 15 2014

Keywords

Crossrefs

For number of solutions to a^2+b^2+c^2+k*d^2=n for k=1, 2, 3, 4, 5, 6, 7, 8, 12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

Formula

G.f.: theta_3(q)^3*theta_3(q^2), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018
G.f.: 1 + 8*Sum{n >= 1} n*(q^n - q^(3*n) - q^(5*n) + q^(7*n))/(1 - q^(8*n)) - 2*Sum_{n >= 0} (-1)^((n^2+n)/2)*(2*n+1)q^(2*n+1)/(1 - q^(2*n+1)). See Zucker p. 5. Cf. A117000. - Peter Bala, Feb 25 2021

A236926 Number of integer solutions to a^2 + b^2 + c^2 + 3*d^2 = n.

Original entry on oeis.org

1, 6, 12, 10, 18, 48, 40, 12, 60, 78, 24, 48, 70, 84, 120, 32, 66, 192, 84, 36, 144, 180, 120, 96, 136, 126, 168, 82, 84, 336, 200, 60, 252, 288, 96, 96, 234, 228, 360, 140, 120, 480, 144, 84, 336, 336, 240, 192, 310, 258, 252, 128, 252, 624, 400, 96, 408, 540, 168
Offset: 0

Views

Author

N. J. A. Sloane, Feb 15 2014

Keywords

Crossrefs

Cf. A236924.
For number of solutions to a^2+b^2+c^2+k*d^2=n for k=1,2,3,4,5,6,7,8,12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

Formula

G.f.: theta_3(q)^3*theta_3(q^3), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018

A236930 Number of integer solutions to a^2 + b^2 + c^2 + 5*d^2 = n.

Original entry on oeis.org

1, 6, 12, 8, 6, 26, 36, 24, 28, 42, 72, 72, 8, 48, 108, 48, 54, 64, 84, 120, 26, 72, 144, 88, 84, 126, 216, 80, 24, 180, 156, 192, 92, 96, 288, 144, 42, 144, 240, 144, 168, 252, 144, 168, 72, 182, 396, 184, 72, 258, 372, 192, 48, 208, 360, 312, 252, 160, 360, 360, 48
Offset: 0

Views

Author

N. J. A. Sloane, Feb 16 2014

Keywords

Crossrefs

For number of solutions to a^2+b^2+c^2+k*d^2=n for k=1,2,3,4,5,6,7,8,12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

  • Maple
    See A236924.
  • Mathematica
    Join[{1},Table[Length[Reduce[a^2+b^2+c^2+5d^2==n,{a,b,c,d},Integers]],{n,60}]] (* Harvey P. Dale, Jul 02 2017 *)

Formula

G.f.: theta_3(q)^3*theta_3(q^5), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018

A236931 Number of integer solutions to a^2 + b^2 + c^2 + 6*d^2 = n.

Original entry on oeis.org

1, 6, 12, 8, 6, 24, 26, 12, 36, 46, 36, 72, 56, 24, 72, 60, 54, 96, 52, 72, 120, 48, 36, 96, 98, 90, 144, 144, 60, 120, 144, 60, 180, 172, 96, 240, 142, 72, 192, 96, 132, 288, 180, 120, 216, 168, 144, 192, 152, 162, 276, 256, 120, 216, 210, 120, 264, 256, 180, 360, 300
Offset: 0

Views

Author

N. J. A. Sloane, Feb 16 2014

Keywords

Crossrefs

For number of solutions to a^2 + b^2 + c^2 + k*d^2 = n for k = 1, 2, 3, 4, 5, 6, 7, 8, 12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

Formula

G.f.: theta_3(q)^3*theta_3(q^6), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018

A236932 Number of integer solutions to a^2 + b^2 + c^2 + 7*d^2 = n.

Original entry on oeis.org

1, 6, 12, 8, 6, 24, 24, 2, 24, 54, 40, 36, 56, 72, 48, 24, 66, 96, 84, 40, 72, 144, 24, 12, 120, 102, 120, 80, 98, 132, 72, 64, 84, 240, 160, 48, 198, 180, 120, 72, 136, 240, 240, 84, 84, 312, 120, 96, 248, 246, 180, 96, 216, 228, 240, 80, 156, 360, 216, 120, 168
Offset: 0

Views

Author

N. J. A. Sloane, Feb 16 2014

Keywords

Crossrefs

For number of solutions to a^2 + b^2 + c^2 + k*d^2 = n for k = 1, 2, 3, 4, 5, 6, 7, 8, 12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

Formula

G.f.: theta_3(q)^3*theta_3(q^7), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018

A236933 Number of integer solutions to a^2 + b^2 + c^2 + 12*d^2 = n.

Original entry on oeis.org

1, 6, 12, 8, 6, 24, 24, 0, 12, 30, 24, 24, 10, 36, 72, 16, 18, 96, 84, 24, 48, 108, 72, 48, 40, 78, 168, 32, 12, 168, 120, 48, 60, 144, 96, 48, 78, 84, 216, 64, 24, 240, 144, 24, 48, 168, 144, 96, 70, 114, 252, 64, 84, 312, 240, 48, 120, 252, 168, 120, 32
Offset: 0

Views

Author

N. J. A. Sloane, Feb 16 2014

Keywords

Crossrefs

Different from A005875.
For number of solutions to a^2+b^2+c^2+k*d^2=n for k=1,2,3,4,5,6,7,8,12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

Formula

G.f.: theta_3(q)^3*theta_3(q^12), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 03 2018

A236927 Number of integer solutions to a^2 + b^2 + c^2 + 8*d^2 = n.

Original entry on oeis.org

1, 6, 12, 8, 6, 24, 24, 0, 14, 42, 48, 40, 20, 72, 96, 0, 30, 108, 84, 72, 40, 96, 120, 0, 36, 126, 144, 80, 48, 168, 96, 0, 62, 120, 216, 128, 42, 216, 216, 0, 72, 252, 192, 168, 100, 168, 288, 0, 68, 342, 252, 144, 120, 312, 240, 0, 112, 216, 336, 232, 48, 360, 384
Offset: 0

Views

Author

N. J. A. Sloane, Feb 15 2014

Keywords

Crossrefs

Cf. A236924.
For number of solutions to a^2+b^2+c^2+k*d^2=n for k=1,2,3,4,5,6,7,8,12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

Formula

G.f.: theta_3(q)^3*theta_3(q^8), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018

A320149 Number of integer solutions to a^2 + 2*b^2 + 2*c^2 + 2*d^2 = n.

Original entry on oeis.org

1, 2, 6, 12, 14, 24, 20, 16, 30, 14, 40, 60, 36, 72, 48, 16, 62, 36, 42, 108, 72, 96, 100, 48, 68, 42, 120, 120, 112, 168, 48, 64, 126, 40, 108, 192, 98, 216, 180, 48, 136, 84, 160, 252, 180, 168, 144, 96, 132, 114, 126, 216, 216, 312, 200, 80, 240, 72, 280, 348, 112
Offset: 0

Views

Author

Seiichi Manyama, Oct 06 2018

Keywords

Comments

a(n) > 0 for n >= 0.

Crossrefs

Formula

G.f.: theta_3(q) * theta_3(q^2)^3.

A320150 Number of integer solutions to a^2 + 2*b^2 + 2*c^2 + 3*d^2 = n.

Original entry on oeis.org

1, 2, 4, 10, 10, 16, 24, 12, 28, 26, 8, 48, 30, 28, 72, 32, 34, 64, 28, 36, 80, 60, 72, 96, 72, 42, 56, 82, 36, 112, 120, 60, 124, 96, 32, 96, 130, 76, 216, 140, 56, 160, 48, 84, 144, 112, 144, 192, 150, 86, 84, 128, 140, 208, 240, 96, 216, 180, 56, 240, 96, 124, 360
Offset: 0

Views

Author

Seiichi Manyama, Oct 06 2018

Keywords

Comments

a(n) > 0 for n >= 0.

Crossrefs

Formula

G.f.: theta_3(q) * theta_3(q^2)^2 * theta_3(q^3).
Showing 1-10 of 15 results. Next