A343997 a(n) = A011772(n) if that number is even, otherwise A011772(n)+1.

2, 4, 2, 8, 4, 4, 6, 16, 8, 4, 10, 8, 12, 8, 6, 32, 16, 8, 18, 16, 6, 12, 22, 16, 24, 12, 26, 8, 28, 16, 30, 64, 12, 16, 14, 8, 36, 20, 12, 16, 40, 20, 42, 32, 10, 24, 46, 32, 48, 24, 18, 40, 52, 28, 10, 48, 18, 28, 58, 16, 60, 32, 28, 128, 26, 12, 66, 16, 24, 20, 70, 64, 72, 36, 24, 56, 22, 12, 78, 64, 80

Offset: 1

Author

N. J. A. Sloane, Jun 01 2021

Keywords

• nonn

Links

• N. J. A. Sloane, Table of n, a(n) for n = 1..16383

Crossrefs

Cf. A000217, A011772, A061781, A343996.

Programs

Python

from sympy.ntheory.modular import crt
from sympy import factorint
from itertools import product
def A343997(n):
    fs = factorint(2*n)
    plist = [p**fs[p] for p in fs]
    x = min(k for k in (crt(plist,d)[0] for d in product([0,-1],repeat=len(plist))) if k > 0)
    return x + x % 2 # Chai Wah Wu, Jun 01 2021