OFFSET
0,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (7, -21, 35, -35, 21, -7, 1).
FORMULA
a(n) = (4*n^2+20*n+15)*binomial(n+4, 4)/15.
G.f.: (1+6*x+x^2)/(1-x)^7.
a(0)=1, a(1)=13, a(2)=71, a(3)=259, a(4)=742, a(5)=1806, a(6)=3906, a(n)=7*a(n-1)-21*a(n-2)+35*a(n-3)-35*a(n-4)+21*a(n-5)-7*a(n-6)+a(n-7). - Harvey P. Dale, Dec 16 2012
MATHEMATICA
Table[((4n^2+20n+15)Binomial[n+4, 4])/15, {n, 0, 30}] (* or *) LinearRecurrence[ {7, -21, 35, -35, 21, -7, 1}, {1, 13, 71, 259, 742, 1806, 3906}, 30] (* Harvey P. Dale, Dec 16 2012 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Apr 06 2001
STATUS
approved