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A071570 a(n) = 2*sum(d dividing n, 2^mu(d)). 1
4, 5, 5, 7, 5, 10, 5, 9, 7, 10, 5, 14, 5, 10, 10, 11, 5, 14, 5, 14, 10, 10, 5, 18, 7, 10, 9, 14, 5, 20, 5, 13, 10, 10, 10, 20, 5, 10, 10, 18, 5, 20, 5, 14, 14, 10, 5, 22, 7, 14, 10, 14, 5, 18, 10, 18, 10, 10, 5, 28, 5, 10, 14, 15, 10, 20, 5, 14, 10, 20, 5, 26, 5, 10, 14, 14, 10, 20, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

Asymptotically: sum(k=1, n, a(k)) = 2C*n*log(n)+0(n*log(n)) with C=1.1...

PROG

(PARI) for(n=1, 100, print1(2*sumdiv(n, d, 2^moebius(d)), ", "))

CROSSREFS

Sequence in context: A316150 A110883 A178131 * A336047 A082448 A190796

Adjacent sequences:  A071567 A071568 A071569 * A071571 A071572 A071573

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 31 2002

STATUS

approved

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Last modified December 8 17:01 EST 2021. Contains 349596 sequences. (Running on oeis4.)