Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #15 Jun 13 2015 00:48:35
%S 1,1,1,3,4,5,6,9,13,18,24,33,46,64,88,121,167,231,319,440,607,838,
%T 1157,1597,2204,3042,4199,5796,8000,11042,15241,21037,29037,40079,
%U 55320,76357,105394,145473,200793,277150
%N a(n) = a(n-1) + a(n-4), starting 1,1,1,3.
%H Vincenzo Librandi, <a href="/A014101/b014101.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,1).
%F G.f.: (-2*x^3-1)/(x^4+x-1). - _Harvey P. Dale_, Aug 29 2012
%F a(n) = 2*A003269(n-2) + A003269(n+1), n>1. - _Ralf Stephan_, Aug 15 2013
%t 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 *)
%K nonn,easy
%O 0,4
%A _N. J. A. Sloane_.