OFFSET
1,1
COMMENTS
Every term is even.
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) = (2*n + n^2 + 2*n^3 + 3*n^4)/4.
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) = 2*x*(1 + 4*x + 4*x^2) and g(x) = (1-x)^5.
MATHEMATICA
(See A213828.)
LinearRecurrence[{5, -10, 10, -5, 1}, {2, 18, 78, 230, 540}, 30] (* Harvey P. Dale, Jan 11 2015 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jul 04 2012
STATUS
approved