A121910 a(n) = 3*a(n-1)*a(n-2)*a(n-3)*a(n-4) - a(n-5), with a(1)=a(2)=a(3)=a(4)=a(5)=1.
1, 1, 1, 1, 1, 2, 5, 29, 869, 756029, 285790302433, 16335219393063437264866, 9201358366190200404401435237110861938769705
Offset: 1
Keywords
Links
- G. C. Greubel, Table of n, a(n) for n = 1..17
Programs
-
GAP
a:= function(n) if n<6 then return 1; else return 3*a(n-1)*a(n-2)*a(n-3)*a(n-4) - a(n-5); fi; end; List([1..15], n-> a(n) ); # G. C. Greubel, Oct 05 2019 -
Magma
[n lt 6 select 1 else 3*Self(n-1)*Self(n-2)*Self(n-3)*Self(n-4) - Self(n-5): n in [1..15]]; // G. C. Greubel, Oct 07 2019
-
Maple
a:= proc(n) option remember; if n<6 then 1 else 3*a(n-1)*a(n-2)*a(n-3)*a(n-4) - a(n-5) fi; end: seq(a(n), n=1..15); # G. C. Greubel, Oct 07 2019 -
Mathematica
a[n_]:= a[n]= If[n<6, 1, 3*a[n-1]*a[n-2]*a[n-3]*a[n-4] - a[n-5]]; Table[a[n], {n, 15}] (* modified by G. C. Greubel, Oct 07 2019 *) -
PARI
my(m=15, v=concat([1,1,1,1,1], vector(m-5))); for(n=6, m, v[n] = 3*v[n-1] *v[n-2]*v[n-3]*v[n-4] - v[n-5]); v \\ G. C. Greubel, Oct 07 2019
-
Sage
def a(n): if (n<6): return 1 else: return 3*a(n-1)*a(n-2)*a(n-3)*a(n-4) - a(n-5) [a(n) for n in (1..15)] # G. C. Greubel, Oct 07 2019
Extensions
Edited by N. J. A. Sloane, Sep 15 2006
Definition adapted to offset by Georg Fischer, Jun 18 2021
Comments