OFFSET
1,2
COMMENTS
Essentially a duplicate of A011764. - N. J. A. Sloane, Oct 06 2009
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..14
FORMULA
MATHEMATICA
a[1]:= 1; a[2]:= 3; a[n_]:= Product[a[j], {j, 1, n-1}]; Table[a[n], {n, 1, 12}] (* G. C. Greubel, Oct 19 2018 *)
nxt[{prd_, a_}]:=Module[{c=prd*a}, {c, prd*a}]; Join[{1, 3}, Rest[ NestList[ nxt, {1, 3}, 10][[All, 1]]]] (* Harvey P. Dale, Jan 31 2022 *)
PROG
(PARI) {a(n) = if(n==1, 1, if(n==2, 3, prod(j=1, n-1, a(j))))};
for(n=1, 10, print1(a(n), ", ")) \\ G. C. Greubel, Oct 19 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Sep 17 2009
STATUS
approved