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A071872 Number of positive k such that k*tau(k) <= n. 0
0, 2, 1, 1, 3, 2, 4, 3, 3, 3, 5, 4, 6, 5, 7, 6, 6, 6, 6, 6, 6, 6, 8, 7, 9, 8, 10, 11, 10, 10, 10, 10, 12, 11, 13, 12, 12, 12, 14, 13, 15, 14, 14, 14, 14, 14, 16, 15, 15, 15, 15, 15, 15, 15, 15, 15, 17, 16, 18, 17, 19, 18, 20, 19, 19, 19, 19, 19, 19, 19, 19, 19, 21, 20, 22, 23, 22, 22 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

For n > 80, does always a(n) > Pi(n) the primes counting function ?

LINKS

Table of n, a(n) for n=1..78.

PROG

(PARI) for(n=1, 100, print1(sum(i=1, n, if(sign(n-i*numdiv(i))-1, 0, 1))+sum(i=1, n, if(n-i*numdiv(i)-1, 0, 1)), ", "))

CROSSREFS

Sequence in context: A319849 A117334 A241472 * A141038 A240055 A156309

Adjacent sequences:  A071869 A071870 A071871 * A071873 A071874 A071875

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Jun 09 2002

STATUS

approved

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Last modified October 23 23:51 EDT 2019. Contains 328379 sequences. (Running on oeis4.)