A360491 - OEIS

A360491

Square of A(n,m) read by antidiagonals. A(n,m) = number of set partitions of [5n] into 5-element subsets {i, i+k, i+2k, i+3k, i+4k} with 1 <= k <= m.

1, 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 2, 4, 5, 1, 1, 2, 4, 7, 8, 1, 1, 2, 4, 10, 13, 13, 1, 1, 2, 4, 10, 19, 24, 21, 1, 1, 2, 4, 10, 20, 41, 44, 34, 1, 1, 2, 4, 10, 21, 43, 84, 81, 55, 1, 1, 2, 4, 10, 21, 58, 89, 180, 149, 89, 1, 1, 2, 4, 10, 21, 59, 120, 192, 372, 274, 144, 1

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OFFSET

1,5

LINKS

Table of n, a(n) for n=1..78.

FORMULA

A(n,m) = A104431(n) = A104443(n,5) for m >= floor((5n - 1) / 4).

EXAMPLE

Square array begins:

1, 1, 1, 1, 1, 1, 1, 1, 1, ...

1, 2, 2, 2, 2, 2, 2, 2, 2, ...

1, 3, 4, 4, 4, 4, 4, 4, 4, ...