OFFSET
2,3
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*(2*n^3 - 9*n^2 + 10*n - 3)/12.
GF(z) = (4*z^2 + 8*z - 1)/(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-1)
MATHEMATICA
LinearRecurrence[{8, -24, 32, -16}, {-1, 0, 28, 192}, 30] (* Harvey P. Dale, Jan 22 2012 *)
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