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Difference between maximum and minimum positive value y in solutions to x^2 - y^2 = n!.
0

%I #12 Apr 04 2012 12:15:08

%S 4,28,176,1258,10070,90692,907184,9979181,119750111,1556754911,

%T 21794572379,326918591535,5230697470143,88921857013919,

%U 1600593426385151,30411275101997759,608225502043759679

%N Difference between maximum and minimum positive value y in solutions to x^2 - y^2 = n!.

%F a(n) = A139174(n) - A038202(n).

%t cc = {}; Do[f = n!/4; x = Max[Select[Divisors[f], # <= Sqrt[f] &]]; kk = f/x - x; kkk = ((n! - 4)/4); AppendTo[cc, kkk - kk], {n, 4, 20}]; cc

%K nonn,easy

%O 4,1

%A _Artur Jasinski_, Mar 31 2012