A219678 Number of tripartite partitions of (n,n,n) into triples.

1, 5, 66, 686, 6721, 58616, 476781, 3608348, 25781989, 174810494, 1132328205, 7037425172, 42140788751, 243918472743, 1368647208107, 7462686474948, 39626100989332, 205283558905562, 1039263967957447, 5149048724566723, 24998922141116056, 119073277412589351

Offset

0,2

Comments

a(n) is also the number of factorizations of m^n where m is a product of 3 distinct primes. a(1) = 5: (2*3*5)^1 = 30 has 5 factorizations: 30, 5*6, 3*10, 2*3*5, 2*15.

Links

Sean A. Irvine, Table of n, a(n) for n = 0..29

Example

a(1) = 5: [(1,1,1)], [(1,1,0),(0,0,1)], [(1,0,1),(0,1,0)], [(1,0,0),(0,1,0),(0,0,1)], [(0,1,1),(1,0,0)].

Crossrefs

Column k=3 of A219727.

Cf. A219560.

Sequence in context: A263786 A169934 A162443 * A297743 A279463 A361409

Adjacent sequences: A219675 A219676 A219677 * A219679 A219680 A219681

Keyword

nonn

Author

Alois P. Heinz, Nov 26 2012

Extensions

More terms from Sean A. Irvine, Aug 14 2014

Status

approved