A216641 Number of nondecreasing arrays of n 1..n integers with the sum of their 3rd powers equal to sum(i^3,i=1..n).

1, 1, 1, 1, 1, 2, 2, 6, 12, 30, 76, 224, 597, 1801, 5469, 16958, 53308, 169872, 548344, 1791949, 5915441, 19700851, 66148464, 223751776, 761919971, 2610778118, 8998428171, 31179152130, 108577507149, 379879051198

Offset

1,6

Comments

Column 3 of A216645

Links

Table of n, a(n) for n=1..30.

Example

All solutions for n=8
..1....3....1....2....2....1
..1....4....2....2....2....2
..4....5....2....2....4....3
..5....6....5....3....4....4
..5....6....5....6....4....5
..5....6....7....7....4....6
..7....6....7....7....8....7
..8....6....7....7....8....8

Crossrefs

Sequence in context: A027375 A059727 A103872 * A191970 A376837 A175516

Adjacent sequences: A216638 A216639 A216640 * A216642 A216643 A216644

Keyword

nonn

Author

R. H. Hardin, Sep 11 2012

Status

approved