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A074944 Number of k with 1 <= k <= n such that gcd(n,k)=tau(k), where tau is A000005, number of divisors function. 1
1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 4, 1, 2, 2, 2, 1, 3, 1, 3, 2, 2, 1, 4, 1, 2, 1, 3, 1, 5, 1, 3, 2, 2, 1, 3, 1, 2, 2, 3, 1, 5, 1, 3, 2, 2, 1, 5, 1, 2, 2, 3, 1, 3, 1, 4, 2, 2, 1, 5, 1, 2, 2, 5, 1, 5, 1, 3, 2, 2, 1, 5, 1, 2, 2, 3, 1, 5, 1, 4, 2, 2, 1, 7, 1, 2, 2, 5, 1, 4, 1, 3, 2, 2, 1, 9, 1, 2, 2, 3, 1, 5, 1, 6, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

FORMULA

Sum_{i=1..n} a(i) seems to be asymptotic to c*n*log(n) with 0.5 < c < 0.6.

PROG

(PARI) a(n)=sum(k=1, n, if(gcd(n, k)-numdiv(k), 0, 1))

CROSSREFS

Cf. A000005.

Sequence in context: A161288 A185217 A131456 * A245041 A161315 A161249

Adjacent sequences:  A074941 A074942 A074943 * A074945 A074946 A074947

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Oct 05 2002

STATUS

approved

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Last modified October 20 20:24 EDT 2019. Contains 328273 sequences. (Running on oeis4.)