cp's OEIS Frontend

A271950 Somos's sequence {b(5,n)} defined in comment in A078495: a(0)=a(1)=...=a(12)=1; for n>=13, a(n)=(a(n-1)*a(n-12)+a(n-6)*a(n-7))/a(n-13).

%I A271950 #27 Sep 08 2022 08:46:16
%S A271950 1,1,1,1,1,1,1,1,1,1,1,1,1,2,3,4,5,6,7,9,15,27,47,77,119,301,519,827,
%T A271950 1351,2345,4263,10598,35021,91652,200923,396578,742721,2258305,
%U A271950 5126953,14354017,45716169,138331649,377080865,1330892225,5490413305,16470110241
%N A271950 Somos's sequence {b(5,n)} defined in comment in A078495: a(0)=a(1)=...=a(12)=1; for n>=13, a(n)=(a(n-1)*a(n-12)+a(n-6)*a(n-7))/a(n-13).
%H A271950 Seiichi Manyama, <a href="/A271950/b271950.txt">Table of n, a(n) for n = 0..392</a>
%t A271950 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 A271950 Map[a[5,#]&,Range[0,50]] (* _Peter J. C. Moses_, Apr 17 2016 *)
%t A271950 RecurrenceTable[{a[0]==a[1]==a[2]==a[3]==a[4]==a[5]==a[6]==a[7]== a[8]== a[9]== a[10]== a[11] ==a[12]==1,a[n]==(a[n-1]a[n-12]+a[n-6]a[n-7])/a[n-13]},a,{n,50}] (* _Harvey P. Dale_, May 01 2018 *)
%o A271950 (PARI) {a(n) = if(n< 12, 1, (a(n-1)*a(n-12) + a(n-6)*a(n-7))/a(n-13))};
%o A271950 for(n=0,40, print1(a(n), ", ")) \\ _G. C. Greubel_, Feb 21 2018
%o A271950 (Magma) [n le 13 select 1 else ((Self(n-1)*Self(n-12) + Self(n-6)*Self(n- 7) )/Self(n-13)): n in [1..40]]; // _G. C. Greubel_, Feb 21 2018
%Y A271950 Cf.  A006721, A078495, A268199, A271948, A271949.
%K A271950 nonn
%O A271950 0,14
%A A271950 _Vladimir Shevelev_ and _Peter J. C. Moses_, Apr 17 2016