cp's OEIS Frontend

A271955 Somos's sequence {b(8,n)} defined in comment in A078495: a(0)=a(1)=...=a(18)=1; for n>=19, a(n)=(a(n-1)*a(n-18)+a(n-9)*a(n-10))/a(n-19).

%I A271955 #20 Sep 08 2022 08:46:16
%S A271955 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,3,4,5,6,7,8,9,10,12,18,30,50,
%T A271955 80,122,178,250,340,800,1308,1924,2780,4136,6452,10476,17348,28720,
%U A271955 61664,179696,439304,910464,1686704,2905792,4793624,7753616,12537856
%N A271955 Somos's sequence {b(8,n)} defined in comment in A078495: a(0)=a(1)=...=a(18)=1; for n>=19, a(n)=(a(n-1)*a(n-18)+a(n-9)*a(n-10))/a(n-19).
%H A271955 Seiichi Manyama, <a href="/A271955/b271955.txt">Table of n, a(n) for n = 0..533</a>
%t A271955 a[k_,n_]:=a[k,n]=If[n>2k+2,(a[k,(n-1)]*a[k,(n-2k-2)]+a[k,(n-k-1)]*a[k,(n-k-2)])/a[k,(n-2k-3)],1];
%t A271955 Map[a[8,#]&,Range[0,50]] (* _Peter J. C. Moses_, Apr 17 2016 *)
%o A271955 (PARI) {a(n) = if(n<= 19, 1, (a(n-1)*a(n-18) + a(n-9)*a(n-10))/a(n-19))}; for(n=1,50, print1(a(n), ", ")) \\ _G. C. Greubel_, Jul 30 2018
%o A271955 (Magma) [n le 19 select 1 else (Self(n-1)*Self(n-18)+Self(n-9)*Self(n-10))/Self(n-19): n in [1..60]]; // _G. C. Greubel_, Jul 30 2018
%Y A271955 Cf. A006721, A078495, A268199, A271948, A271949, A271950, A271952, A271954.
%K A271955 nonn
%O A271955 0,20
%A A271955 _Vladimir Shevelev_ and _Peter J. C. Moses_, Apr 17 2016