OFFSET
1,2
EXAMPLE
a(5)=144 for 33!=8683317618811886495518194401280000000 whose sum of digits is 144=12^2. a(5) is also originated from 34! and 35!.
MATHEMATICA
Union[Select[Total[IntegerDigits[#]]&/@(Range[2500]!), IntegerQ[Sqrt[#]]&]] (* Harvey P. Dale, Feb 20 2015 *)
PROG
(PARI) lista(nn) = {v = vector(nn, n, sumdigits(n!)); Set(select(x->issquare(x), v)); } \\ Michel Marcus, May 18 2014
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Carmine Suriano, May 17 2014
STATUS
approved