A283819 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=5.

1, 1, 1, 1, 1, 4, 7, 34, 271, 9481, 644701, 873569821, 16564630945531, 53396170676073896674, 93290566519166645800556706007, 7726619025447530237307166997354575113953764, 825143736463592166562339930949661527263208803232441071667816341

Offset

1,6

Links

Seiichi Manyama, Table of n, a(n) for n = 1..24

Matthew Christopher Russell, Using experimental mathematics to conjecture and prove theorems in the theory of partitions and commutative and non-commutative recurrences, PhD Dissertation, Mathematics Department, Rutgers University, May 2016; see also.

Mathematica

a[n_]:=If[n<6, 1, (1 + Sum[a[n - j] * a[n - j - 1], {j, 3}])/a[n - 5]]; Table[a[n], {n, 1, 17}] (* Indranil Ghosh, Mar 17 2017 *)

Prog

(PARI) a(n) = if(n<6, 1, (1 + sum(j=1, 3, a(n - j) * a(n - j - 1)))/a(n - 5));
for(n=1, 17, print1(a(n), ", ")) \\ Indranil Ghosh, Mar 17 2017

Crossrefs

Sequence in context: A103059 A123809 A140981 * A124624 A209480 A209339

Adjacent sequences: A283816 A283817 A283818 * A283820 A283821 A283822

Keyword

nonn

Author

N. J. A. Sloane, Mar 17 2017

Extensions

More terms from Indranil Ghosh, Mar 17 2017

Status

approved