OFFSET
2,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 2..1000
W. Griffiths, R. Smith and D. Warren, Almost avoiding pairs of permutations, PU. M. A. Vol. 22 (2011), 129-139.
Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
FORMULA
G.f.: x^3*(11*x^3-25*x^2+8*x-6)/(x-1)^5. [Colin Barker, Oct 17 2012]
a(n) = 5*a(n-1)-10*a(n-2)+10*a(n-3)-5*a(n-4)+a(n-5). - Wesley Ivan Hurt, Nov 10 2014
MAPLE
MATHEMATICA
Table[n^4/2 - 5 n^3/2 + 21 n - 30, {n, 2, 40}] (* Vincenzo Librandi, Mar 11 2013 *)
LinearRecurrence[{5, -10, 10, -5, 1}, {0, 6, 22, 75, 204}, 40] (* Harvey P. Dale, Dec 12 2018 *)
PROG
(Maxima) makelist(n^4/2-5*n^3/2+21*n-30, n, 2, 40); /* Martin Ettl, Oct 15 2012 */
(Magma) [n^4/2-5*n^3/2+21*n-30: n in [2..40]]; // Vincenzo Librandi, Mar 11 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Oct 13 2012
STATUS
approved