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.

A106254 Partition table in square format.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 3, 3, 2, 1, 1, 3, 4, 3, 2, 1, 1, 4, 5, 5, 3, 2, 1, 1, 4, 7, 6, 5, 3, 2, 1, 1, 5, 8, 9, 7, 5, 3, 2, 1, 1, 5, 10, 11, 10, 7, 5, 3, 2, 1, 1, 6, 12, 15, 13, 11, 7, 5, 3, 2, 1, 1, 6, 14, 18, 18, 14, 11, 7, 5, 3, 2, 1, 1, 7, 16, 23, 23, 20, 15, 11, 7, 5, 3, 2, 1
Offset: 1

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Author

Gary W. Adamson, Apr 27 2005

Keywords

Comments

The square is the following table:
1 1 1 1 1 1 1...
1 2 2 2 2 2 2...
1 2 3 3 3 3 3...
1 3 4 5 5 5 5...
1 3 5 6 7 7 7...
1 4 7 9 10 11 11...
1 4 8 11 13 14 15...

Examples

			The partitions of 6 are:
1 + 1 + 1 + 1 + 1 + 1; 2 + 1 + 1 + 1 + 1; 3 + 1 + 1 + 1; 2 + 2 + 1 + 1; 4 + 1 + 1; 3 + 2 + 1; 2 + 2 + 2; 5 + 1, 4 + 2, 3 + 3, 6.
There are 9 partitions of 6 having summands no larger than 4, so p_4(6) = 9.
		

References

  • Ivan Niven, "Mathematics of Choice, How to Count Without Counting", MAA, 1965, pp. 98-99 (table p. 98).

Crossrefs

Essentially the same as A008284, except for missing one diagonal thereof (which would be zero row of this array).

Programs

  • Mathematica
    T[n_, k_] := T[n, k] = If[n == 0 || k == 1, 1, T[n, k-1] + If[k > n, 0, T[n-k, k]]];
    Table[T[n-k+1, k], {n, 1, 13}, {k, 1, n}] // Flatten (* Jean-François Alcover, Aug 08 2018, after Alois P. Heinz *)

Formula

Antidiagonals of table of values of p_k(n) (the number of partitions of n with no summand greater than k).
T(n,m) = sum_{i=1..m} A008284(n,i). T(n,m) = A026820(n,m) if m<=n and T(n,m)=T(n,n) if m>=n. G.f. column m: 1/(1-x)/(1-x^2)/.../(1-x^m) = sum_(n=1,2,3..) T(n,m) x^n [Comtet]. - R. J. Mathar, Aug 31 2007

Extensions

Edited, corrected and extended by Franklin T. Adams-Watters, Jan 12 2006