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A326129
a(n) = gcd(A326127(n), A326128(n)).
13
1, 1, 2, 1, 4, 0, 6, 1, 1, 2, 10, 1, 12, 4, 6, 1, 16, 1, 18, 1, 10, 8, 22, 6, 1, 10, 2, 21, 28, 12, 30, 1, 18, 14, 22, 1, 36, 16, 22, 10, 40, 12, 42, 1, 4, 20, 46, 1, 1, 1, 30, 3, 52, 12, 38, 2, 34, 26, 58, 3, 60, 28, 2, 1, 46, 12, 66, 1, 42, 4, 70, 1, 72, 34, 2, 3, 58, 12, 78, 1, 1, 38, 82, 7, 62, 40, 54, 2, 88, 2, 70, 1, 58, 44, 70, 30
OFFSET
1,3
COMMENTS
Question: Are there any other numbers than those in A000396 that satisfy a(k) = A326128(k)?
See also comments in A336641, where all such k should reside. - Antti Karttunen, Jul 29 2020
LINKS
FORMULA
a(n) = n - A336645(n). - Antti Karttunen, Jul 29 2020
PROG
(PARI)
A326127(n) = (sigma(n)-core(n)-n);
A326128(n) = (n-core(n));
A326129(n) = gcd(A326127(n), A326128(n));
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 09 2019
STATUS
approved