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A356876
Binary weight of the composite numbers (A002808).
1
1, 2, 1, 2, 2, 2, 3, 4, 1, 2, 2, 3, 3, 2, 3, 3, 4, 3, 4, 1, 2, 2, 3, 2, 3, 4, 2, 3, 3, 4, 4, 2, 3, 3, 4, 3, 4, 5, 3, 4, 4, 4, 5, 6, 1, 2, 2, 2, 3, 3, 2, 3, 4, 3, 4, 4, 2, 3, 3, 3, 4, 4, 5, 3, 4, 5, 4, 5, 5, 6, 2, 3, 4, 3, 4, 3, 4, 4, 4, 5, 6, 3, 4, 5, 4, 5, 5, 6, 4, 5, 5
OFFSET
1,2
LINKS
FORMULA
a(n) = A000120(A002808(n)).
MATHEMATICA
DigitCount[#, 2, 1] & /@ Select[Range[125], CompositeQ] (* Amiram Eldar, Oct 03 2022 *)
PROG
(Python)
from sympy import isprime
print([bin(k)[2:].count("1") for k in range(4, 123) if not isprime(k)])
(PARI) forcomposite (k=0, 120, print1 (hammingweight(k), ", ")) \\ Hugo Pfoertner, Oct 03 2022
CROSSREFS
KEYWORD
base,nonn,easy
AUTHOR
Karl-Heinz Hofmann, Oct 02 2022
STATUS
approved