A217944 Number of different lattices formed by intersections of two composition series of length n.

1, 1, 2, 5, 17, 73, 397, 2623, 20414, 181607, 1809104, 19886032, 238723606

Offset

0,3

Comments

For computer programs and tables of first 100 terms of A217944 and A217945 see the authors' web sites.

Links

Table of n, a(n) for n=0..12.

Gábor Czédli, László Ozsvárt, and Balázs Udvari, How many ways can two composition series intersect?, Discrete Math. 312 (2012), no. 24, 3523--3536. MR2979481.

Crossrefs

Cf. A217945.

Sequence in context: A102038 A002135 A260337 * A007868 A136726 A112831

Adjacent sequences: A217941 A217942 A217943 * A217945 A217946 A217947

Keyword

nonn,more

Author

N. J. A. Sloane, Nov 07 2012

Status

approved