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A372608
a(n) = Sum_{k=1..n} phi(n*k).
2
1, 3, 10, 18, 44, 40, 114, 124, 198, 192, 430, 292, 708, 540, 704, 888, 1552, 954, 2178, 1456, 1980, 2080, 3806, 2216, 4220, 3480, 4734, 4056, 7588, 3560, 9270, 6960, 7920, 7840, 9936, 7296, 15588, 10980, 13056, 11120, 21240, 10128, 24570, 16360, 17880, 19360, 32062
OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Totient Function.
FORMULA
a(n) = A372606(n,n).
a(n) = A000010(n) * A070639(n).
PROG
(PARI) a(n) = sum(k=1, n, eulerphi(k*n));
CROSSREFS
Main diagonal of A372606.
Sequence in context: A210286 A275988 A177955 * A298976 A265487 A074893
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 07 2024
STATUS
approved