A014101 a(n) = a(n-1) + a(n-4), starting 1,1,1,3.

1, 1, 1, 3, 4, 5, 6, 9, 13, 18, 24, 33, 46, 64, 88, 121, 167, 231, 319, 440, 607, 838, 1157, 1597, 2204, 3042, 4199, 5796, 8000, 11042, 15241, 21037, 29037, 40079, 55320, 76357, 105394, 145473, 200793, 277150

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (1,0,0,1).

Programs

Mathematica

LinearRecurrence[{1,0,0,1},{1,1,1,3},40] (* or *) CoefficientList[ Series[ (-1-2 x^3)/(-1+x+x^4),{x,0,40}],x] (* Harvey P. Dale, Aug 29 2012 *)

Formula

G.f.: (-2*x^3-1)/(x^4+x-1). - Harvey P. Dale, Aug 29 2012

a(n) = 2*A003269(n-2) + A003269(n+1), n>1. - Ralf Stephan, Aug 15 2013