A131211 a(n)=(n^5-n-30)/30.

-1, -1, 0, 7, 33, 103, 258, 559, 1091, 1967, 3332, 5367, 8293, 12375, 17926, 25311, 34951, 47327, 62984, 82535, 106665, 136135, 171786, 214543, 265419, 325519, 396044, 478295, 573677, 683703, 809998, 954303, 1118479, 1304511, 1514512, 1750727, 2015537, 2311463, 2641170, 3007471, 3413331

Offset: 0

Author

Artur Jasinski, Oct 20 2007, Nov 15 2007

Keywords

• sign

Comments

All numbers generated by the polynomial x^5-x-1 (see A126426) are congruent to 29 mod 30. The polynomial n^5-n-30 factors as (n-2)(n^4+2n^3+4n^2+8n+15)

Crossrefs

Cf. A126426, A134326, A134327.

Programs

Mathematica

Table[((n^5 - n - 1) - 29)/30, {n, -1, 100}]

Formula

a(n) = ((n^5 - n - 1) - 29)/30

G.f.: (-1+5*x-9*x^2+12*x^3-4*x^4+x^5)/(-1+x)^6. - R. J. Mathar, Nov 14 2007