A242538 - OEIS

%I #15 Feb 20 2015 17:50:54

%S 1,9,36,81,144,225,324,441,729,1089,1296,2025,2304,2601,2916,3249,

%T 3600,3969,4356,4761,6561,7056,7569,8100,8649,9216,9801,10404,11025,

%U 11664,12996,13689,15129,16641,17424,20736,22500,23409,26244,29241

%N Squares that are sum of digits of factorials.

%C Intersection of A000290 and A004152.

%e a(5)=144 for 33!=8683317618811886495518194401280000000 whose sum of digits is 144=12^2. a(5) is also originated from 34! and 35!.

%t Union[Select[Total[IntegerDigits[#]]&/@(Range[2500]!),IntegerQ[Sqrt[#]]&]] (* _Harvey P. Dale_, Feb 20 2015 *)

%o (PARI) lista(nn) = {v = vector(nn, n, sumdigits(n!)); Set(select(x->issquare(x), v));} \\ _Michel Marcus_, May 18 2014

%Y Cf. A066235.

%K nonn,base

%O 1,2

%A _Carmine Suriano_, May 17 2014