OFFSET
1,3
COMMENTS
a(n) is the sum over all elements of Alt_n of the size of their conjugacy class. Each conjugacy class is thus counted as many times as its size, giving a sum of squares.
EXAMPLE
For n=5, a(5) = 1 + 12^2 + 12^2 + 15^2 + 20^2 = 914.
The class equation of A_5 is 1 + 12 + 12 + 15 + 20 = 60 = 5!/2
PROG
(GAP) A206820 := n -> Sum(ConjugacyClasses(AlternatingGroup(n)), c->Size(c)^2); # Eric M. Schmidt, Jan 26 2014
CROSSREFS
KEYWORD
nonn,nice,easy
AUTHOR
Olivier Gérard, Feb 12 2012
EXTENSIONS
More terms from Eric M. Schmidt, Jan 26 2014
STATUS
approved