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A074945 Number of k with 1<=k<=n such that gcd(n,k) = floor(n/k). 0
1, 0, 1, 2, 2, 1, 3, 2, 4, 3, 5, 2, 6, 4, 4, 6, 8, 4, 9, 4, 7, 7, 11, 5, 11, 8, 9, 7, 14, 6, 15, 9, 11, 11, 12, 9, 18, 12, 13, 10, 20, 8, 21, 11, 13, 15, 23, 10, 22, 13, 17, 15, 26, 13, 21, 15, 20, 19, 29, 10, 30, 20, 18, 20, 24, 14, 33, 19, 24, 16, 35, 15, 36, 24, 22, 22, 30, 18, 39 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..79.

FORMULA

a(n) <= n/2 It seems that limit_inf n ->infinity a(n)/n = 0.1.....

PROG

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

CROSSREFS

Sequence in context: A058741 A339491 A291712 * A323479 A276427 A129711

Adjacent sequences:  A074942 A074943 A074944 * A074946 A074947 A074948

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Oct 05 2002

STATUS

approved

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Last modified April 17 11:26 EDT 2021. Contains 343064 sequences. (Running on oeis4.)