Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #19 Mar 18 2024 11:21:43
%S 0,1,2,0,1,2,0,2,4,0,0,0,0,1,2,0,2,4,0,0,0,0,2,4,0,4,8,0,0,0,0,0,0,0,
%T 0,0,0,0,0,0,1,2,0,2,4,0,0,0,0,2,4,0,4,8,0,0,0,0,0,0,0,0,0,0,0,0,0,2,
%U 4,0,4,8,0,0,0,0,4,8,0,8,16,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
%N Product of digits of (n written in base 3).
%H Seiichi Manyama, <a href="/A309953/b309953.txt">Table of n, a(n) for n = 0..10000</a>
%F G.f. A(x) satisfies: A(x) = x * (1 + 2*x) * (1 + A(x^3)).
%p a:= proc(n) a(n):= `if`(n<3, n, irem(n, 3, 'q')*a(q)) end:
%p seq(a(n), n=0..100); # _Alois P. Heinz_, Mar 18 2024
%t Table[Times @@ IntegerDigits[n, 3], {n, 0, 100}]
%o (PARI) a(n) = {if(n, vecprod(digits(n,3)), 0)} \\ _Andrew Howroyd_, Aug 24 2019
%o (Magma) [0] cat [&*Intseq(n,3):n in [1..100]]; // _Marius A. Burtea_, Aug 25 2019
%Y Cf. A007089, A007954, A053735.
%K nonn,base,look
%O 0,3
%A _Ilya Gutkovskiy_, Aug 24 2019