cp's OEIS Frontend

A271949 Somos's sequence {b(4,n)} defined in comment in A078495: a(0)=a(1)=...=a(10)=1; for n>=11, a(n)=(a(n-1)*a(n-10)+a(n-5)*a(n-6))/a(n-11).

%I A271949 #26 Sep 08 2022 08:46:16
%S A271949 1,1,1,1,1,1,1,1,1,1,1,2,3,4,5,6,8,14,26,46,76,200,356,596,1044,1952,
%T A271949 5136,17888,48376,109520,225248,724672,1749280,5359328,18277312,
%U A271949 57803136,235710976,1067767168,3411743616,9748806656,29696723456,156028988416
%N A271949 Somos's sequence {b(4,n)} defined in comment in A078495: a(0)=a(1)=...=a(10)=1; for n>=11, a(n)=(a(n-1)*a(n-10)+a(n-5)*a(n-6))/a(n-11).
%H A271949 Seiichi Manyama, <a href="/A271949/b271949.txt">Table of n, a(n) for n = 0..343</a>
%t A271949 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 A271949 Map[a[4,#]&,Range[0,50]] (* _Peter J. C. Moses_, Apr 17 2016 *)
%t A271949 RecurrenceTable[{Table[a[d]==1,{d,0,10}],a[n]==(a[n-1]a[n-10]+ a[n-5]a[n-6])/ a[n-11]},a,{n,50}] (* _Harvey P. Dale_, Oct 18 2021 *)
%o A271949 (PARI) {a(n) = if(n< 11, 1, (a(n-1)*a(n-10) + a(n-5)*a(n-6))/a(n-11))};
%o A271949 for(n=0,30, print1(a(n), ", ")) \\ _G. C. Greubel_, Feb 21 2018
%o A271949 (Magma) [n le 11 select 1 else (Self(n-1)*Self(n-10) + Self(n-5)*Self(n- 6))/Self(n-11): n in [1..30]]; // _G. C. Greubel_, Feb 21 2018
%Y A271949 Cf.  A006721, A078495, A268199, A271948.
%K A271949 nonn
%O A271949 0,12
%A A271949 _Vladimir Shevelev_ and _Peter J. C. Moses_, Apr 17 2016