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 1-3 of 3 results.

A347805 Expansion of (theta_3(x) - 1)^2 / (2 * (3 - theta_3(x))).

Original entry on oeis.org

1, 1, 1, 3, 4, 5, 7, 10, 16, 22, 30, 43, 62, 88, 123, 175, 249, 354, 502, 710, 1006, 1427, 2024, 2869, 4068, 5767, 8176, 11593, 16436, 23301, 33033, 46832, 66398, 94137, 133461, 189211, 268252, 380315, 539192, 764433, 1083764, 1536498, 2178364, 3088365, 4378502, 6207581, 8800750
Offset: 2

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Author

Ilya Gutkovskiy, Sep 14 2021

Keywords

Comments

Number of compositions (ordered partitions) of n into two or more squares.

Crossrefs

Programs

  • Maple
    b:= proc(n, t) option remember; `if`(n=0, `if`(t=0, 1, 0), add((
         s->`if`(s>n, 0, b(n-s, max(0, t-1))))(j^2), j=1..isqrt(n)))
        end:
    a:= n-> b(n, 2):
    seq(a(n), n=2..48);  # Alois P. Heinz, Sep 14 2021
  • Mathematica
    nmax = 48; CoefficientList[Series[(EllipticTheta[3, 0, x] - 1)^2/(2 (3 - EllipticTheta[3, 0, x])), {x, 0, nmax}], x] // Drop[#, 2] &

Formula

From Alois P. Heinz, Sep 14 2021: (Start)
a(n) = A006456(n) - A010052(n).
a(n) = Sum_{k=2..n} A337165(n,k). (End)

A348528 Number of partitions of n into two or more distinct triangular numbers.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 2, 1, 1, 2, 1, 1, 2, 0, 2, 3, 1, 1, 2, 2, 1, 4, 3, 0, 3, 3, 1, 4, 3, 3, 3, 2, 3, 3, 2, 3, 6, 4, 2, 5, 4, 2, 6, 5, 3, 6, 6, 3, 5, 5, 5, 6, 5, 4, 7, 7, 5, 8, 6, 5, 9, 7, 4, 9, 9, 6, 10, 9, 3, 9, 10, 8, 11, 11, 9, 10, 10, 9, 10, 10, 9
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 21 2021

Keywords

Crossrefs

A348326 Number of compositions (ordered partitions) of n into two or more distinct squares.

Original entry on oeis.org

0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 2, 6, 0, 0, 2, 0, 0, 2, 6, 0, 0, 0, 2, 8, 0, 0, 8, 30, 0, 0, 0, 2, 6, 0, 2, 6, 24, 2, 8, 6, 0, 0, 8, 30, 0, 0, 6, 32, 24, 2, 8, 30, 120, 6, 24, 2, 6, 0, 8, 36, 24, 0, 34, 150, 0, 2, 12, 30, 24, 0, 2, 38, 150, 0, 12, 78, 144, 2, 30, 122, 6
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 12 2021

Keywords

Examples

			For n = 14 there exists the following six solutions: 1+4+9 = 1+9+4 = 4+1+9 = 4+9+1 = 9+1+4 = 9+4+1 = 14, therefore a(14) = 6. - _Antti Karttunen_, Oct 17 2021
		

Crossrefs

Showing 1-3 of 3 results.