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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.

A097306 Array of number of partitions of n with odd parts not exceeding 2*m-1 with m in {1, 2, ..., ceiling(n/2)}.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 2, 3, 1, 3, 4, 1, 3, 4, 5, 1, 3, 5, 6, 1, 4, 6, 7, 8, 1, 4, 7, 9, 10, 1, 4, 8, 10, 11, 12, 1, 5, 9, 12, 14, 15, 1, 5, 10, 14, 16, 17, 18, 1, 5, 11, 16, 19, 21, 22, 1, 6, 13, 19, 23, 25, 26, 27, 1, 6, 14, 21, 26, 29, 31, 32, 1, 6, 15, 24, 30, 34, 36, 37, 38, 1, 7, 17, 27
Offset: 1

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Author

Wolfdieter Lang, Aug 13 2004

Keywords

Comments

The sequence of row lengths of this array is A008619 = [1,1,2,2,3,3,4,4,5,5,6,6,7,7,...].
This is the partial row sums array of array A097305.
The number of partitions of N=2*n (n >= 1) into even parts not exceeding 2*k, with k from {1,...,n}, is given by the triangle A026820(n,k).

Examples

			[1]; [1]; [1,2]; [1,2]; [1,2,3]; [1,3,4]; [1,3,4,5]; [1,3,5,6]; ...
T(8,2)=3 because there are three partitions of 8 with odd parts not exceeding 3, namely (1^8), (1^5,3) and (1^2,3^2).
T(6,2)=3 from the partitions (1^6), (1^3,3) and (3^2).
		

Crossrefs

Row sums: A097307.

Programs

  • Maple
    Sequence of row numbers for n>=1: [seq(coeff(series(product(1/(1-x^(2*k-1)),k=1..p),x,n+1),x,n),p=1..ceil(n/2))].

Formula

T(n, m) = number of partitions of n with odd parts only and largest parts <= 2*m-1 for m from {1, 2, ..., ceiling(n/2)}.
T(n, m) = Sum_{k=1..m} A097305(n, k), m = 1..ceiling(n/2), n >= 1.