A348367 a(n) = w(n + w(n)), where w(n) is the binary weight of n, A000120(n).

1, 2, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 3, 2, 3, 2, 3, 3, 2, 3, 4, 3, 3, 4, 5, 5, 2, 2, 2, 2, 3, 2, 3, 3, 2, 3, 4, 3, 3, 4, 5, 5, 3, 3, 3, 3, 3, 4, 5, 5, 4, 4, 4, 5, 5, 5, 1, 1, 2, 3, 3, 2, 3, 2, 3, 3, 2, 3, 4, 3, 3, 4, 5, 5, 3, 3, 3, 3, 3, 4, 5, 5, 4, 4, 4, 5, 5, 5, 2, 2, 3, 4, 4, 3, 3, 4, 5

Offset: 1

Author

Ctibor O. Zizka, Oct 15 2021

Keywords

• nonn
• base

Examples

			n = 5; a(5) = A000120(5 + A000120(5)) = 3.
		

Crossrefs

Cf. A000120, A092391.

Programs

Mathematica

h[n_] := DigitCount[n, 2, 1]; a[n_] := h[n + h[n]]; Array[a, 100] (* Amiram Eldar, Oct 15 2021 *)

PARI

a(n) = hammingweight(n + hammingweight(n)); \\ Michel Marcus, Oct 17 2021

Python

def h(n): return bin(n).count('1')
def a(n): return h(n + h(n))
print([a(n) for n in range(1, 100)]) # Michael S. Branicky, Oct 15 2021

Formula

a(n) = A000120(n + A000120(n)); a(n) = A000120(A092391(n)).