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A322979 a(n) = Sum A009191(d) over the divisors d of n, where A009191(x) = gcd(x, A000005(x)), and A000005(x) gives the number of divisors of x. 2
1, 3, 2, 4, 2, 6, 2, 8, 5, 6, 2, 13, 2, 6, 4, 9, 2, 15, 2, 9, 4, 6, 2, 25, 3, 6, 6, 9, 2, 12, 2, 11, 4, 6, 4, 31, 2, 6, 4, 21, 2, 12, 2, 9, 10, 6, 2, 28, 3, 9, 4, 9, 2, 18, 4, 21, 4, 6, 2, 33, 2, 6, 10, 12, 4, 12, 2, 9, 4, 12, 2, 55, 2, 6, 8, 9, 4, 12, 2, 32, 7, 6, 2, 33, 4, 6, 4, 21, 2, 30, 4, 9, 4, 6, 4, 42, 2, 9, 10, 13, 2, 12, 2, 21, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Inverse Möbius transform of A009191.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10080

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..100000

FORMULA

a(n) = Sum_{d|n} A009191(d).

PROG

(PARI)

A009191(n) = gcd(n, numdiv(n));

A322979(n) = sumdiv(n, d, A009191(d));

CROSSREFS

Cf. A009191.

Sequence in context: A157220 A304182 A256284 * A106288 A013633 A016559

Adjacent sequences:  A322976 A322977 A322978 * A322980 A322981 A322982

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jan 05 2019

STATUS

approved

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Last modified February 28 23:08 EST 2020. Contains 332351 sequences. (Running on oeis4.)