A343996 a(n) = A011772(n) if that number is odd, otherwise A011772(n)+1.

1, 3, 3, 7, 5, 3, 7, 15, 9, 5, 11, 9, 13, 7, 5, 31, 17, 9, 19, 15, 7, 11, 23, 15, 25, 13, 27, 7, 29, 15, 31, 63, 11, 17, 15, 9, 37, 19, 13, 15, 41, 21, 43, 33, 9, 23, 47, 33, 49, 25, 17, 39, 53, 27, 11, 49, 19, 29, 59, 15, 61, 31, 27, 127, 25, 11, 67, 17, 23, 21, 71, 63, 73, 37, 25, 57, 21, 13, 79, 65, 81, 41

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, A343997.

Programs

Python

from sympy.ntheory.modular import crt
from sympy import factorint
from itertools import product
def A343996(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 + 1 - x % 2 # Chai Wah Wu, Jun 01 2021