a(n) = (1 + Sum_{j=1..K-1} a(n-j) + a(n-1)*a(n-K+1))/a(n-K) with a(1),...,a(K)=1, where K=4.

A283329

a(n) = (1 + Sum_{j=1..K-1} a(n-j) + a(n-1)*a(n-K+1))/a(n-K) with a(1),...,a(K)=1, where K=4.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =5a(5) =13a(6) =33a(7) =217a(8) =617a(9) =1633a(10) =10813a(11) =30805a(12) =81601a(13) =540401a(14) =1539601a(15) =4078401a(16) =27009205a(17) =76949213a(18) =203838433a(19) =1349919817a(20) =3845921017a(21) =10187843233a(22) =67468981613a(23) =192219101605a(24) =509188323201

External references