A134327 a(n) = (n^5-n-5)/5.

-1, -1, 5, 47, 203, 623, 1553, 3359, 6551, 11807, 19997, 32207, 49763, 74255, 107561, 151871, 209711, 283967, 377909, 495215, 639995, 816815, 1030721, 1287263, 1592519, 1953119, 2376269, 2869775, 3442067, 4102223, 4859993, 5725823, 6710879, 7827071, 9087077, 10504367, 12093227, 13868783

Offset: 0

Author

Artur Jasinski, Oct 20 2007

Keywords

• sign
• easy

Comments

All numbers generated by polynomial A131176 are congruent to 4 mod 5.

The polynomial n^5-n-5 is irreducible.

Links

• Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).

Crossrefs

Cf. A131176.

Programs

Mathematica

Table[((n^5 - n - 1) - 4)/5, {n, 0, 100}]

PARI

a(n) = (n^5-n-5)/5; \\ Jinyuan Wang, Mar 12 2020

Formula

a(n) = ((n^5 - n - 1) - 4)/5

G.f.: (-1+5*x-4*x^2+22*x^3+x^4+x^5)/(-1+x)^6. - R. J. Mathar, Nov 14 2007