A127228 a(n) = numerator of ((n + 4)! - (n - 4)!)/(n!).

40319, 362879, 1814399, 6652799, 19958399, 51891839, 121080959, 259459199, 518918399, 980179199, 1764322559, 3047466239, 5079110399, 8204716799, 12893126399, 19769460479, 29654190719, 43609103999, 62990927999

Offset: 4

Author

Artur Jasinski, Jan 09 2007

Keywords

• nonn
• frac

Links

• Robert Israel, Table of n, a(n) for n = 4..10000

Crossrefs

Cf. A028387, A062938, A127227, A127229, A127230.

Programs

Maple

f::= n -> (n+4)*(n+3)*(n+2)*(n+1)*n*(n-1)*(n-2)*(n-3)-1:
map(f, [$4..30]); # Robert Israel, Nov 20 2023

Mathematica

Table[Numerator[((n + 4)! - (n - 4)!)/(n!)], {n, 4, 30}]

Formula

a(n) = (n+4) * (n+3) * (n+2) * (n+1) * n * (n-1) * (n-2) * (n-3) - 1. - Robert Israel, Nov 20 2023