OFFSET
0,2
LINKS
Zhuorui He, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
FORMULA
A007318 * [1, 5, 10, 10, 5, 1, 1, -1, 1, -1, 1, ...]
From Emeric Deutsch, Jun 03 2008: (Start)
a(n) = n*(274 + 85*n^2 + n^4)/60 for n >= 1. [corrected by Zhuorui He, Mar 01 2026]
G.f.: (1+x^6)/(1-x)^6. (End)
E.g.f.: 1 + exp(x)*x*(360 + 270*x + 110*x^2 + 10*x^3 + x^4)/60. - Stefano Spezia, Mar 02 2026
EXAMPLE
a(4) = 56 = (1, 3, 3, 1) dot (1, 5, 10, 10) = (1 + 15 + 30 + 10).
MAPLE
1, seq((1/60)*n*(274+85*n^2+n^4), n=1..30); # Emeric Deutsch, Jun 03 2008
MATHEMATICA
LinearRecurrence[{6, -15, 20, -15, 6, -1}, {1, 6, 21, 56, 126, 252, 463}, 50] (* Paolo Xausa, Apr 03 2026 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, May 12 2008
EXTENSIONS
More terms from Emeric Deutsch, Jun 03 2008
More terms from Zhuorui He, Mar 01 2026
STATUS
approved
