OFFSET
1,2
LINKS
Clark Kimberling, 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*(1 + n)*(1 - 2*n + 4*n^2)/6.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5).
G.f.: f(x)/g(x), where f(x) = x*(1 + x)(1 + 8*x) and g(x) = (1-x)^5.
MAPLE
A213843:=n->n*(1 + n)*(1 - 2*n + 4*n^2)/6: seq(A213843(n), n=1..30); # Wesley Ivan Hurt, Oct 09 2014
MATHEMATICA
Table[n (1 + n) (1 - 2 n + 4 n^2)/6, {n, 30}] (* Wesley Ivan Hurt, Oct 09 2014 *)
PROG
(Magma) [n*(1 + n)*(1 - 2*n + 4*n^2)/6 : n in [1..30]]; // Wesley Ivan Hurt, Oct 09 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jul 05 2012
STATUS
approved