A161989 - OEIS

A161989

Numbers having more than 2 or fewer than 2 ones in their binary representation.

0, 1, 2, 4, 7, 8, 11, 13, 14, 15, 16, 19, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 35, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 67, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

COMMENTS

A000120(a(n)) <> 2.

Complement of A018900; A151774(a(n)) = 0.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MATHEMATICA

Select[Range[0, 100], DigitCount[#, 2, 1]!=2&] (* Harvey P. Dale, Mar 11 2013 *)

PROG

(PARI) isok(n) = hammingweight(n) != 2; \\ Michel Marcus, Nov 01 2019