OFFSET
1,3
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).
FORMULA
a(n) = n*(n-1)*(3*n^2+n-12)/4.
a(n) = 5*a(n-1)-10*a(n-2)+10*a(n-3)-5*a(n-4)+a(n-5) for n>5. - Colin Barker, May 28 2015
G.f.: x^2*(5*x^2-22*x-1) / (x-1)^5. - Colin Barker, May 28 2015
MATHEMATICA
LinearRecurrence[{5, -10, 10, -5, 1}, {0, 1, 27, 120, 340}, 50] (* Harvey P. Dale, Jan 10 2022 *)
PROG
(Magma) [n*(n-1)*(3*n^2+n-12)/4: n in [1..45]]; // Vincenzo Librandi, Jun 30 2011
(PARI) concat(0, Vec(x^2*(5*x^2-22*x-1) / (x-1)^5 + O(x^100))) \\ Colin Barker, May 28 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paolo Dominici (pl.dm(AT)libero.it)
STATUS
approved