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A373060
a(n) = Sum_{1 <= x_1, x_2, x_3 <= n} gcd(x_1, n)/gcd(x_1, x_2, x_3, n).
3
1, 11, 43, 115, 221, 473, 631, 1139, 1609, 2431, 2531, 4945, 4213, 6941, 9503, 10867, 9521, 17699, 13339, 25415, 27133, 27841, 23783, 48977, 39721, 46343, 55555, 72565, 47909, 104533, 58591, 100979, 108833, 104731, 139451, 185035, 99901, 146729, 181159, 251719
OFFSET
1,2
LINKS
PROG
(PARI) a(n) = sum(i=1, n, sum(j=1, n, sum(k=1, n, gcd(i, n)/gcd([i, j, k, n]))));
CROSSREFS
Sequence in context: A352966 A142039 A196153 * A213763 A302226 A201714
KEYWORD
nonn,mult
AUTHOR
Seiichi Manyama, May 21 2024
STATUS
approved