OFFSET

0,7

COMMENTS

a(n) is also the number of connected even partitions of n in the following sense. Given a partition of n, the vertices are the parts of the partition and two vertices are connected if and only if their gcd is greater than 1. We call a partition connected if the graph is connected.

LINKS

Liam Naughton and Goetz Pfeiffer, Integer sequences realized by the subgroup pattern of the symmetric group, arXiv:1211.1911 and J. Int. Seq. 16 (2013) #13.5.8

Liam Naughton, CountingSubgroups.g

Liam Naughton and Goetz Pfeiffer, Tomlib, The GAP table of marks library

CROSSREFS

KEYWORD

nonn,more

AUTHOR

Liam Naughton, Nov 28 2012

STATUS

approved