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

1,6

Links

G. C. Greubel, Table of n, a(n) for n = 1..17

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 *)

Prog

(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
(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
(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
(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

Crossrefs

Cf. A072879, A121897.

Sequence in context: A098717 A059784 A000283 * A073833 A229918 A179554

Adjacent sequences: A121907 A121908 A121909 * A121911 A121912 A121913

Keyword

nonn

Author

Roger L. Bagula, Sep 09 2006

Extensions

Edited by N. J. A. Sloane, Sep 15 2006

Definition adapted to offset by Georg Fischer, Jun 18 2021

Status

approved