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
KEYWORD
base,nonn
AUTHOR
Tanya Khovanova, Dec 27 2006
EXTENSIONS
More terms from Emeric Deutsch, Jan 01 2007
STATUS
approved