A099562 Sum C(n-4k,k-1), k=0..floor(n/5).

0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 3, 4, 5, 6, 7, 11, 15, 20, 26, 33, 45, 60, 80, 106, 139, 185, 245, 325, 431, 570, 756, 1001, 1326, 1757, 2327, 3084, 4085, 5411, 7168, 9495, 12580, 16665, 22076, 29244, 38739, 51320, 67985, 90061, 119305, 158044, 209365

Offset: 0

Author

Paul Barry, Oct 22 2004

Keywords

• easy
• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,2,-1,0,0,0,-1).

Crossrefs

Cf. A075331, A099560, A099561.

Programs

Mathematica

Table[Sum[Binomial[n-4k,k-1],{k,0,Floor[n/5]}],{n,0,60}] (* or *) LinearRecurrence[{1,0,0,0,2,-1,0,0,0,-1},{0,0,0,0,0,1,1,1,1,1},60] (* Harvey P. Dale, Jul 14 2015 *)

Formula

G.f.: x^5/((1-x^5)(1-x-x^5)); a(n)=a(n-1)+2a(n-5)-a(n-6)-a(n-10).