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%I #17 Feb 17 2023 16:48:56
%S 1,4,5,6,7,8,9,10,11,13,14,15,16
%N Indices of squares in A068869.
%C a(14) > 30000. - _Michel Marcus_, Jan 30 2023
%e 5 is a term because A068869(5) = 1 is a square;
%e 8 is a term because A068869(8) = 81 is a square.
%o (PARI) isok(n) = issquare((sqrtint(n!-1)+1)^2-n!); \\ _Michel Marcus_, Jan 30 2023
%Y Cf. A068869.
%K nonn,more
%O 1,2
%A _Alexander R. Povolotsky_, Jan 29 2023