OFFSET
1,1
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = (2*n - 9*n^2 + 16*n^3)/3.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4).
G.f.: f(x)/g(x), where f(x) = x*(3 + 20*x + 9*x^2) and g(x) = (1-x)^4.
MATHEMATICA
(See A213841.)
LinearRecurrence[{4, -6, 4, -1}, {3, 32, 119, 296}, 40] (* Harvey P. Dale, Nov 06 2014 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jul 05 2012
STATUS
approved