A239426 21*n^4 - 36*n^3 + 25*n^2 - 8*n + 1.

1, 3, 133, 931, 3441, 9211, 20293, 39243, 69121, 113491, 176421, 262483, 376753, 524811, 712741, 947131, 1235073, 1584163, 2002501, 2498691, 3081841, 3761563, 4547973, 5451691, 6483841, 7656051, 8980453, 10469683, 12136881, 13995691, 16060261, 18345243

Offset: 0

Author

Reinhard Zumkeller, Mar 19 2014

Keywords

• nonn
• easy

Comments

For n > 0: a(n) = A219069(2*n-1,n).

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
• Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

Programs

Haskell

a239426 n = (((21 * n - 36) * n + 25) * n - 8) * n + 1

Magma

[21*n^4-36*n^3+25*n^2-8*n+1: n in [0..31]]; // Vincenzo Librandi, Mar 21 2014

Mathematica

Table[(21 n^4 - 36 n^3 + 25 n^2 - 8 n + 1), {n, 0, 40}] (* Vincenzo Librandi, Mar 21 2014 *)
LinearRecurrence[{5,-10,10,-5,1},{1,3,133,931,3441},40] (* Harvey P. Dale, May 04 2016 *)

Formula

a(n) = (1-3*n+3*n^2) * (1-5*n+7*n^2) = A003215(n-1) * A239449(n).

G.f.: ( -1+2*x-128*x^2-286*x^3-91*x^4 ) / (x-1)^5 . - R. J. Mathar, Mar 31 2014