|
|
A117592
|
|
a(n) = a(3n) = a(3n+1) = a(3n+2)/2 with a(0)=1.
|
|
9
|
|
|
1, 1, 2, 1, 1, 2, 2, 2, 4, 1, 1, 2, 1, 1, 2, 2, 2, 4, 2, 2, 4, 2, 2, 4, 4, 4, 8, 1, 1, 2, 1, 1, 2, 2, 2, 4, 1, 1, 2, 1, 1, 2, 2, 2, 4, 2, 2, 4, 2, 2, 4, 4, 4, 8, 2, 2, 4, 2, 2, 4, 4, 4, 8, 2, 2, 4, 2, 2, 4, 4, 4
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
Row sums of number triangle A117944.
Product of the nonzero digits of (n written in base 3). - Ilya Gutkovskiy, Nov 15 2020
a(n) = 1, 2, 4, 8, 16, 32, 64 iff n is respectively in A005836, A023699, A023700, A023701, A023702, A023703, A023704. - Bernard Schott, Dec 04 2020
|
|
LINKS
|
|
|
FORMULA
|
a(n) = a(3n)/a(0) = a(3n+1)/a(1) = a(3n+2)/a(2).
G.f. A(x) satisfies: A(x) = (1 + x + 2*x^2) * A(x^3). - Ilya Gutkovskiy, Nov 15 2020
|
|
MATHEMATICA
|
|
|
PROG
|
(PARI) a(n) = 1 << hammingweight(digits(n, 3)>>1); \\ Kevin Ryde, Nov 15 2020
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|