A125495 Composite odious numbers.

4, 8, 14, 16, 21, 22, 25, 26, 28, 32, 35, 38, 42, 44, 49, 50, 52, 55, 56, 62, 64, 69, 70, 74, 76, 81, 82, 84, 87, 88, 91, 93, 94, 98, 100, 104, 110, 112, 115, 117, 118, 121, 122, 124, 128, 133, 134, 138, 140, 143, 145, 146, 148, 152, 155, 158, 161, 162, 164, 168, 171

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

49 is in the sequence since it is composite and base-2 representation (110001) has an odd number of 1's.

Maple

a:=proc(n) local n2: n2:=convert(n, base, 2): if add(n2[j], j=1..nops(n2)) mod 2 = 1 and isprime(n)=false then n else fi end: seq(a(n), n=2..210); # Emeric Deutsch, Jan 01 2007

Mathematica

Select[Range[171], OddQ @ DigitCount[#, 2][[1]] && CompositeQ[#] &] (* Amiram Eldar, Dec 09 2019 *)

Crossrefs

Intersection of A002808 (the composite numbers) and A000069 (odious numbers).

Sequence in context: A312255 A312256 A229937 * A246158 A312257 A312258

Adjacent sequences: A125492 A125493 A125494 * A125496 A125497 A125498

Keyword

base,nonn

Author

Tanya Khovanova, Dec 27 2006

Extensions

More terms from Emeric Deutsch, Jan 01 2007

Status

approved