%I #17 Aug 04 2022 16:40:21
%S 6,8,10,14,15,16,21,22,26,27,33,34,35,38,39,46,51,55,57,58,62,64,65,
%T 69,74,77,81,82,85,86,87,91,93,94,95,106,111,115,118,119,122,123,125,
%U 129,133,134,141,142,143,145,146,155,158,159,161,166,177,178,183,185,187
%N Natural numbers such that d(n)!+ 1 is a square, where d(n) is the number of divisors of n, A000005.
%C It is generally assumed that the Diophantine equation n! + 1 = m^2 can only be solved for n = 4,5,7. - _Stefan Steinerberger_, Aug 21 2007
%H Harvey P. Dale, <a href="/A130763/b130763.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[1000], IntegerQ[Sqrt[Length[Divisors[ # ]]! + 1]] &] (* _Stefan Steinerberger_, Aug 21 2007 *)
%t Select[Range[200],IntegerQ[Sqrt[DivisorSigma[0,#]!+1]]&] (* _Harvey P. Dale_, Aug 04 2022 *)
%Y Cf. A000005.
%K nonn
%O 1,1
%A _Giovanni Teofilatto_, Aug 17 2007
%E More terms from _Stefan Steinerberger_, Aug 21 2007