OFFSET
4,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 4..1000
Index entries for linear recurrences with constant coefficients, signature (8, -28, 56, -70, 56, -28, 8, -1).
FORMULA
a(n) = (54*n^7 - 1057*n^6 + 7245*n^5 - 24535*n^4 + 45801*n^3 - 47488*n^2 + 25020*n - 5040)/7!.
G.f.: (z^4 + 23*z^3 + 40*z^2 - 2*z - 8)/(z-1)^8.
a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8).
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) = 2*27.
MATHEMATICA
LinearRecurrence[{8, -28, 56, -70, 56, -28, 8, -1}, {-8, -66, -264, -689, -1255, -1360, 684, 8502}, 50] (* G. C. Greubel, Jul 17 2016 *)
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Johannes W. Meijer, Nov 23 2009
STATUS
approved