A074252 - OEIS

A074252

Number of primes <= n is equal to the sum of squarefree numbers from the smallest prime factor of n to the largest prime factor of n.

1, 4, 12, 30, 84, 9150, 47244, 75360, 177287, 281868, 705790, 3043504, 9669715, 20139930, 32043111, 67447484, 291217662, 7544909388, 8396469108, 21425170627

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..19.

EXAMPLE

pi(84) = 23 and 84 = 2^2*3*7 and 2+3+5+6+7 = 23.

CROSSREFS

Cf. A000720.

Sequence in context: A162740 A324943 A301875 * A297079 A074210 A299053

Adjacent sequences: A074249 A074250 A074251 * A074253 A074254 A074255

KEYWORD

more,nonn

AUTHOR

Jason Earls, Sep 20 2002

EXTENSIONS

a(6)-a(19) from Donovan Johnson, Oct 12 2008

STATUS

approved