cp's OEIS Frontend

A268199 Somos's sequence {b(3,n)} defined in comment in A078495: a(0)=a(1)=...=a(8)=1; for n>=9, a(n)=(a(n-1)*a(n-8)+a(n-4)*a(n-5))/a(n-9).

%I A268199 #30 Sep 08 2022 08:46:15
%S A268199 1,1,1,1,1,1,1,1,1,2,3,4,5,7,13,25,45,125,233,419,805,2252,8343,23554,
%T A268199 55889,195533,514781,1769117,6540689,31873013,162776741,568710437,
%U A268199 1840702289,10169970946,53308101423,363030298268,1933899726085,12286029791291
%N A268199 Somos's sequence {b(3,n)} defined in comment in A078495: a(0)=a(1)=...=a(8)=1; for n>=9, a(n)=(a(n-1)*a(n-8)+a(n-4)*a(n-5))/a(n-9).
%H A268199 Seiichi Manyama, <a href="/A268199/b268199.txt">Table of n, a(n) for n = 0..292</a>
%F A268199 a(n) = a(8-n) for all n in Z. - _Michael Somos_, Nov 16 2016
%t A268199 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 A268199 Map[a[3,#]&,Range[0,50]] (* _Peter J. C. Moses_, Apr 16 2016 *)
%t A268199 a[ n_] := a[n] = Which[ n<0, a[8-n], n<9, 1, True, (a[n - 1] a[n - 8] + a[n - 4] a[n - 5]) / a[n - 9]]; (* _Michael Somos_, Nov 16 2016 *)
%o A268199 (PARI) {a(n) = if(n<= 8, 1, (a(n-1)*a(n-8)+a(n-4)*a(n-5))/a(n-9))};
%o A268199 for(n=1,40, print1(a(n), ", ")) \\ _G. C. Greubel_, Feb 21 2018
%o A268199 (Magma) [n le 9 select 1 else (Self(n-1)*Self(n-8) + Self(n-4)*Self(n-5)) /Self(n-9): n in [1..40]]; // _G. C. Greubel_, Feb 21 2018
%Y A268199 Cf. A006721, A078495, A271948.
%K A268199 nonn
%O A268199 0,10
%A A268199 _Vladimir Shevelev_ and _Peter J. C. Moses_, Apr 16 2016