A162943 a(n) = 2^(1-A002321(n)).

1, 2, 4, 4, 8, 4, 8, 8, 8, 4, 8, 8, 16, 8, 4, 4, 8, 8, 16, 16, 8, 4, 8, 8, 8, 4, 4, 4, 8, 16, 32, 32, 16, 8, 4, 4, 8, 4, 2, 2, 4, 8, 16, 16, 16, 8, 16, 16, 16, 16, 8, 8, 16, 16, 8, 8, 4, 2, 4, 4, 8, 4, 4, 4, 2, 4, 8, 8, 4, 8, 16, 16, 32, 16, 16, 16, 8

Offset: 1

Author

Mats Granvik, Jul 18 2009

Keywords

• nonn

Crossrefs

Cf. A002321, first column of A162944.

Programs

Python

from functools import lru_cache
@lru_cache(maxsize=None)
def A162943(n):
    if n == 0:
        return 2
    c, j = n, 2
    k1 = n//j
    while k1 > 1:
        j2 = n//k1 + 1
        c += (j2-j)*(4-len(bin(A162943(k1))))
        j, k1 = j2, n//j2
    return 2**(1+c-j) # Chai Wah Wu, Mar 30 2021