A160569 a(n)=9*(a(n-1)a(n-3)-a(n-2)^2)/a(n-4), a(1)=a(2)=a(3)=1, a(4)=-9.
1, 1, 1, -9, -90, -1539, 51759, 7026831, 1349328699, -119669884380, -462804380329131, -818173230956710191, -775566981773559330471, 23349606875054800260574779, 383206716517298992863985977570
Offset: 0
Links
- Harvey P. Dale, Table of n, a(n) for n = 0..79
Programs
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Mathematica
nxt[{a_,b_,c_,d_}]:={b,c,d,(9(d*b-c^2))/a}; NestList[nxt,{1,1,1,-9},20][[All,1]] (* Harvey P. Dale, Feb 21 2022 *)
Comments