OFFSET
0,7
FORMULA
G.f.: (1-x^2-x^3)/(1-x-x^2+x^4-x^6).
MAPLE
a[0]:=1: a[1]:=1: a[2]:=1: a[3]:=1: a[4]:=1: a[5]:=1: for n from 6 to 45 do a[n]:=a[n-1]+a[n-2]-a[n-4]+a[n-6] od: seq(a[n], n=0..45);
MATHEMATICA
F[1] = 1; F[2] = 1; F[3] = 1; F[4] = 1; F[5] = 1; F[6] = 1; F[n__] := F[n] = F[n - 1] + F[n - 2] - F[n - 4] + F[n - 6] aa = Table[F[n], {n, 1, 50}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Roger L. Bagula, Jun 19 2005
STATUS
approved