OFFSET
0,4
COMMENTS
Quadrisection of sequence with g.f. 1/(1 - x^3 - x^4), or A017817.
LINKS
Index entries for linear recurrences with constant coefficients, signature (4,-6,5,-1).
FORMULA
G.f.: (1-x)^3/((1-x)^4-x^3).
a(n) = sum_{k=0..2n} binomial(k, 4n-3k).
a(n) = 4a(n-1) - 6a(n-2) + 5a(n-3) - a(n-4).
a(n) = A017817(4n).
a(n) = sum_{k=0..floor((n+1)/2)} binomial(n+k, 4k). - Paul Barry, May 09 2005
MATHEMATICA
Join[{1}, a=0; b=0; c=0; d=1; Table[a+=b; b+=c; c+=d; d+=a, {n, 50}]] (* Vladimir Joseph Stephan Orlovsky, Nov 19 2010 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Sep 29 2004
STATUS
approved