A107253 a(n) = n^4 - 15*n + 15.

1, 1, 51, 211, 565, 1221, 2311, 3991, 6441, 9865, 14491, 20571, 28381, 38221, 50415, 65311, 83281, 104721, 130051, 159715, 194181, 233941, 279511, 331431, 390265, 456601, 531051, 614251, 706861, 809565, 923071, 1048111, 1185441, 1335841

Offset: 1

Author

Andras Erszegi (erszegi.andras(AT)chello.hu), May 14 2005

Keywords

• nonn
• easy

Comments

a(n) == A109009(n) (mod 10). - Michel Marcus, Sep 05 2013

Examples

			a(2) = 2^4 - 15*2 + 15 = 1;
a(4) = 4^4 - 15*4 + 15 = 211.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

Programs

Magma

[n^4 - 15*n + 15: n in [1..40]]; // Vincenzo Librandi, Sep 06 2013

Mathematica

Table[(n^4 - 15 n + 15), {n, 1, 40}] (* Vincenzo Librandi, Sep 06 2013 *)
LinearRecurrence[{5,-10,10,-5,1},{1,1,51,211,565},40] (* Harvey P. Dale, Nov 23 2019 *)

PARI

a(n) = n^4 - 15*n + 15; \\ Michel Marcus, Sep 05 2013

Formula

G.f.: x*(1-4*x+56*x^2-44*x^3+15*x^4)/(1-x)^5. - Vincenzo Librandi, Sep 06 2013

Extensions

Definition clarified by Ralf Stephan, Nov 18 2010.