OFFSET
4,2
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) = (27*n^7 - 287*n^6 + 1113*n^5 - 1925*n^4 + 1428*n^3 - 308*n^2 - 48*n)/7!.
G.f.: (1*z^3 + 12*z^2 + 14*z + 0)/(1-z)^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) = 27.
MATHEMATICA
LinearRecurrence[{8, -28, 56, -70, 56, -28, 8, -1}, {0, 14, 124, 601,
2120, 6096, 15168, 33858}, 100] (* G. C. Greubel, Jun 16 2016 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Johannes W. Meijer, Nov 10 2009
EXTENSIONS
Formulae and links added by Johannes W. Meijer, Nov 23 2009
STATUS
approved