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 1-4 of 4 results.

A045847 Matrix whose (i,j)-th entry is number of representations of j as a sum of i squares of nonnegative integers; read by diagonals.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 0, 0, 1, 3, 1, 0, 0, 1, 4, 3, 0, 1, 0, 1, 5, 6, 1, 2, 0, 0, 1, 6, 10, 4, 3, 2, 0, 0, 1, 7, 15, 10, 5, 6, 0, 0, 0, 1, 8, 21, 20, 10, 12, 3, 0, 0, 0, 1, 9, 28, 35, 21, 21, 12, 0, 1, 1, 0, 1, 10, 36, 56, 42, 36, 30, 4, 3, 2, 0, 0, 1, 11, 45, 84, 78, 63, 61, 20, 6, 6, 2, 0, 0
Offset: 0

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Author

Keywords

Examples

			Rows are
1,0,0,..;
1,1,0,0,1,0..;
1,2,1,0,2,2,..;
1,3,3,1,...
		

Crossrefs

Diagonal gives A287617.
Antidiagonal sums give A302018.

Formula

i-th row is expansion of (1+x+x^4+x^9+...)^i.

Extensions

More terms from Erich Friedman

A340915 Number of ways to write n as an ordered sum of 8 squares of positive integers.

Original entry on oeis.org

1, 0, 0, 8, 0, 0, 28, 0, 8, 56, 0, 56, 70, 0, 168, 64, 28, 280, 84, 168, 280, 176, 420, 224, 345, 560, 392, 616, 420, 848, 924, 336, 1246, 1064, 868, 1464, 988, 1680, 1820, 1120, 1904, 2464, 1932, 1904, 2870, 2752, 2772, 2912, 2892, 4256, 3640, 3248, 4480, 5040, 4760, 3696, 6120
Offset: 8

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Author

Ilya Gutkovskiy, Jan 31 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, t) option remember;
          `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add((s->
          `if`(s>n, 0, b(n-s, t-1)))(j^2), j=1..isqrt(n))))
        end:
    a:= n-> b(n, 8):
    seq(a(n), n=8..64);  # Alois P. Heinz, Jan 31 2021
  • Mathematica
    nmax = 64; CoefficientList[Series[(EllipticTheta[3, 0, x] - 1)^8/256, {x, 0, nmax}], x] // Drop[#, 8] &

Formula

G.f.: (theta_3(x) - 1)^8 / 256, where theta_3() is the Jacobi theta function.

A340999 Number of partitions of n into 8 distinct nonzero squares.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 2, 0, 0, 1, 0, 1, 0, 0, 2, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 3, 0, 0, 1
Offset: 204

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Author

Ilya Gutkovskiy, Feb 02 2021

Keywords

Crossrefs

A341403 Number of nonnegative solutions to (x_1)^2 + (x_2)^2 + ... + (x_8)^2 <= n.

Original entry on oeis.org

1, 9, 37, 93, 171, 283, 479, 767, 1076, 1420, 1952, 2688, 3444, 4228, 5320, 6776, 8262, 9662, 11454, 13918, 16480, 18832, 21772, 25644, 29508, 33044, 37300, 42732, 48340, 53556, 59632, 67472, 75405, 82237, 90189, 100661, 111155, 120403, 131099, 144651, 158469, 170621
Offset: 0

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Author

Ilya Gutkovskiy, Feb 10 2021

Keywords

Comments

Partial sums of A045850.

Crossrefs

Programs

  • Maple
    b:= proc(n, k) option remember; `if`(n=0, 1, `if`(n<0 or k<1, 0,
          b(n, k-1)+add(b(n-j^2, k-1), j=1..isqrt(n))))
        end:
    a:= proc(n) option remember; b(n, 8)+`if`(n>0, a(n-1), 0) end:
    seq(a(n), n=0..41);  # Alois P. Heinz, Feb 10 2021
  • Mathematica
    nmax = 41; CoefficientList[Series[(1 + EllipticTheta[3, 0, x])^8/(256 (1 - x)), {x, 0, nmax}], x]

Formula

G.f.: (1 + theta_3(x))^8 / (256 * (1 - x)).
a(n^2) = A055407(n).
Showing 1-4 of 4 results.