OFFSET
2,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 2..1000
Index entries for linear recurrences with constant coefficients, signature (8,-24,32,-16).
FORMULA
a(n) = 2^n*(n^3 - 6*n^2 + 5*n)/12.
GF(z) = (8*z - 2)/(1-2*z)^4.
a(n) = 8*a(n-1) - 24*a(n-2) + 32*a(n-3) - 16*a(n-4).
a(n) - 7*a(n-1) + 18*a(n-2) - 20*a(n-3) + 8*a(n-4) = 1*2^(n-2).
MATHEMATICA
LinearRecurrence[{8, -24, 32, -16}, {-2, -8, -16, 0}, 100] (* G. C. Greubel, Jun 17 2016 *)
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Johannes W. Meijer, Nov 10 2009
EXTENSIONS
Formulae and links added by Johannes W. Meijer, Nov 23 2009
STATUS
approved