A283918 - OEIS

%I #15 Mar 18 2017 05:09:04

%S 1,1,1,1,1,1,5,9,53,529,28565,15139445,86494677165,145497982245073197,

%T 237449075542565847670095797,

%U 65308811677507188262439443927593494833685,542885242695872953856134304668084060854561472461643166998594129

%N a(n) = (1 + Sum_{j=1..K-2} a(n-j)*a(n-j-1))/a(n-K) with a(1),...,a(K)=1, where K=6.

%H Seiichi Manyama, <a href="/A283918/b283918.txt">Table of n, a(n) for n = 1..23</a>

%t a[n_]:= If[n<7, 1, (1 + Sum[a[n - j] * a[n -j - 1], {j, 4}])/a[ n - 6]]; Table[a[n], {n, 23}] (* _Indranil Ghosh_, Mar 18 2017 *)

%o (PARI) a(n) = if(n<7, 1, (1 + sum(j=1, 4, a(n - j) * a(n - j - 1)))/a(n - 6));

%o for(n=1, 24, print1(a(n),", ")) \\ _Indranil Ghosh_, Mar 18 2017

%Y Cf. A077458 (K=4), A283819 (K=5), this sequence (K=6), A283820 (K=7), A283920 (K=8), A283821 (K=9).

%K nonn

%O 1,7

%A _Seiichi Manyama_, Mar 17 2017