This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A286633 #15 Nov 13 2024 16:41:51
%S A286633 1,2,3,2,6,4,9,3,12,2,6,6,18,8,18,4,24,12,27,6,12,3,9,4,36,4,12,6,36,
%T A286633 2,6,12,48,6,18,12,54,16,36,9,24,24,54,4,18,8,18,6,72,24,54,6,24,12,
%U A286633 27,6,72,36,81,12,12,6,18,18,96,36,81,12,36,6,18,36,108,8,24,18,72,24,54,8,48,12,36,18,108,2,6,24,36,4,12,12,36,3,9,4
%N A286633 Base-3 {digit+1} product of A254103: a(n) = A006047(A254103(n)).
%C A286633 Reflecting the structure of A254103 also this sequence can be represented as a binary tree:
%C A286633 1
%C A286633 |
%C A286633 ...................2...................
%C A286633 3 2
%C A286633 6......../ \........4 9......../ \........3
%C A286633 / \ / \ / \ / \
%C A286633 / \ / \ / \ / \
%C A286633 / \ / \ / \ / \
%C A286633 12 2 6 6 18 8 18 4
%C A286633 24 12 27 6 12 3 9 4 36 4 12 6 36 2 6 12
%C A286633 etc.
%H A286633 Antti Karttunen, <a href="/A286633/b286633.txt">Table of n, a(n) for n = 0..8191</a>
%F A286633 a(n) = A006047(A254103(n)).
%F A286633 For n >= 0, a(A000079(n)) = A042950(n).
%o A286633 (Scheme) (define (A286633 n) (A006047 (A254103 n)))
%o A286633 (Python)
%o A286633 from sympy.ntheory.factor_ import digits
%o A286633 from operator import mul
%o A286633 from functools import reduce
%o A286633 def a006047(n):
%o A286633 d=digits(n, 3)
%o A286633 return reduce(mul, [1 + d[i] for i in range(1, len(d))])
%o A286633 def a254103(n):
%o A286633 if n==0: return 0
%o A286633 if n%2==0: return 3*a254103(n//2) - 1
%o A286633 else: return (3*(1 + a254103((n - 1)//2)))//2
%o A286633 def a(n): return a006047(a254103(n)) # _Indranil Ghosh_, Jun 06 2017
%Y A286633 Cf. A000079, A006047, A042950, A254103, A286586, A286587, A286632.
%K A286633 nonn,base
%O A286633 0,2
%A A286633 _Antti Karttunen_, Jun 03 2017