A036461 Number of 1 digits in base 3 representation of 2^n.

1, 0, 2, 0, 2, 2, 2, 2, 4, 0, 4, 2, 4, 2, 6, 4, 2, 4, 6, 2, 6, 4, 6, 4, 8, 2, 10, 4, 4, 8, 6, 8, 8, 8, 8, 6, 10, 8, 10, 10, 6, 6, 12, 8, 10, 14, 8, 10, 10, 12, 16, 8, 12, 18, 10, 10, 14, 10, 14, 14, 16, 10, 16, 12, 16, 16, 14, 16, 14, 18, 20, 12, 20, 10, 22, 12, 26, 8, 20, 12, 22, 14, 16

Offset: 0

Author

David W. Wilson

Keywords

• base
• nonn

Comments

The number of 1's in the base 3 representation of any even(odd) number is even(odd).

Links

• Robert Israel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A020915 (number of digits), A104320 (number of 0's), A260683 (number of 2's).

Programs

Maple

seq(numboccur(1,convert(2^n,base,3)),n=0..100); # Robert Israel, Apr 04 2018

Mathematica

Table[DigitCount[2^n,3,1],{n,0,120}]  (* Harvey P. Dale, Mar 14 2011 *)

PARI

a(n) = #select(x->(x==1), digits(2^n, 3)); \\ Michel Marcus, Apr 04 2018