A181895 Difference between maximum and minimum positive value y in solutions to x^2 - y^2 = n!.

4, 28, 176, 1258, 10070, 90692, 907184, 9979181, 119750111, 1556754911, 21794572379, 326918591535, 5230697470143, 88921857013919, 1600593426385151, 30411275101997759, 608225502043759679

Offset

4,1

Links

Table of n, a(n) for n=4..20.

Formula

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

Mathematica

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

Crossrefs

Sequence in context: A291918 A223166 A026298 * A264707 A216211 A366810

Adjacent sequences: A181892 A181893 A181894 * A181896 A181897 A181898

Keyword

nonn,easy

Author

Artur Jasinski, Mar 31 2012

Status

approved