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 #5 Mar 30 2012 17:39:18
%S 1,11,80,491,2777,15120,81371,440947,2441334,13976885,83547881,
%T 525082654,3483272777,24413200487,180517606216,1404147099951,
%U 11449330342717,97521479081952,864955731435983,7966538662094103
%N Number of rhyme schemes (see reference for precise definition).
%D J. Riordan, A budget of rhyme scheme counts, pp. 455 - 465 of Second International Conference on Combinatorial Mathematics, New York, April 4-7, 1978. Edited by Allan Gewirtz and Louis V. Quintas. Annals New York Academy of Sciences, 319, 1979.
%H J. Riordan, <a href="/A005000/a005000.pdf">Cached copy of paper</a>
%F a(k)=1. a(n)=k*a(n-1)+A000110(n-1)-A102661(n-1,k-2), k=4.
%Y Cf. A005002, A005003.
%K nonn
%O 4,2
%A _R. J. Mathar_, Jul 15 2008