OFFSET
1,2
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..16384
PROG
(Python)
from itertools import combinations
from math import prod
from sympy import factorint, divisors
from sympy.ntheory.modular import crt
from sympy.ntheory import mobius
def A011772(n):
plist = [p**q for p, q in factorint(2*n).items()]
return 2*n-1 if len(plist) == 1 else min(min(crt([m, 2*n//m], [0, -1])[0], crt([2*n//m, m], [0, -1])[0]) for m in (prod(d) for l in range(1, len(plist)//2+1) for d in combinations(plist, l)))
def A344767(n): return sum(mobius(n//d)*A011772(d) for d in divisors(n, generator=True)) # Chai Wah Wu, Jun 20 2021
CROSSREFS
KEYWORD
AUTHOR
Antti Karttunen, May 30 2021
STATUS
approved