OFFSET
1,3
LINKS
FORMULA
EXAMPLE
For n = 672 = 2^5 * 3^1 * 7^1, and the largest unitary divisor of the sigma(672) [= 2^5 * 3^2 * 7^1] coprime with A003961(672) = 13365 = 3^5 * 5^1 * 11^1 is 2^5 * 7^1 = 224, therefore a(672) = 224.
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 16 2022
STATUS
approved