OFFSET
0,4
LINKS
I. Dolinka, J. East, A. Evangelou, D. FitzGerald, N. Ham, et al., Enumeration of idempotents in diagram semigroups and algebras, arXiv preprint arXiv:1408.2021 [math.GR], 2014.
EXAMPLE
Triangle begins:
1,
1, 1,
4, 7, 1,
25, 70, 18, 1,
225, 921, 331, 34, 1,
2704, 15191, 6880, 995, 55, 1,
41209, 304442, 163336, 29840, 2345, 81, 1,
769129, 7240353, 4411190, 958216, 95760, 4739, 112, 1,
17139600, 200542851, 134522725, 33395418, 3992891, 252770, 8610, 148, 1,
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
N. J. A. Sloane, Mar 14 2015
STATUS
approved