A165424 a(1) = 1, a(2) = 6, a(n) = product of the previous terms for n >= 3.

1, 6, 6, 36, 1296, 1679616, 2821109907456, 7958661109946400884391936, 63340286662973277706162286946811886609896461828096

Offset: 1

Author

Jaroslav Krizek, Sep 17 2009

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..13

Crossrefs

See A173501 for another version. - N. J. A. Sloane, Feb 23 2010

Programs

Mathematica

a[1]:= 1; a[2]:= 6; a[n_]:= Product[a[j], {j,1,n-1}]; Table[a[n],{n,1, 12}] (* G. C. Greubel, Oct 19 2018 *)

PARI

{a(n) = if(n==1, 1, if(n==2, 6, prod(j=1,n-1, a(j))))};
for(n=1,10, print1(a(n), ", ")) \\ G. C. Greubel, Oct 19 2018

Formula

a(1) = 1, a(2) = 6, a(n) = Product_{i=1..n-1} a(i), n >= 3.

a(1) = 1, a(2) = 6, a(n) = A000400(2^(n-3)) = 6^(2^(n-3)), n >= 3.

a(1) = 1, a(2) = 6, a(3) = 6, a(n) = (a(n-1))^2, n >= 4.