A181892 a(n) = (n!/4-1)^2.

25, 841, 32041, 1585081, 101586241, 8229936961, 823010025601, 99584412681601, 14340158060659201, 2423486749613529601, 475003403490910694401, 106875765794608626816001, 27360196043576729389056001, 7907096656596520292861952001, 2561899316737326995063771136001

Offset

4,1

Comments

These are maximal values y^2 in solutions to x^2-y^2=n! which are ((n! + 4)/4)^2 - ((n! - 4)/4)^2 = n!.

Links

Table of n, a(n) for n=4..18.

Formula

a(n) = (A139174(n))^2.

Mathematica

Table[((n! - 4)/4)^2, {n, 4, 20}]

Crossrefs

Cf. A139151 (associated x).

Sequence in context: A151557 A008844 A251925 * A274469 A223258 A209119

Adjacent sequences: A181889 A181890 A181891 * A181893 A181894 A181895

Keyword

nonn,easy

Author

Artur Jasinski, Mar 31 2012

Status

approved