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A082996 a(n) = card{ x <= n : bigomega(x) = 4 }. 2
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 9, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,24

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

FORMULA

a(n) ~ (1/6)*(n/log(n))*log(log(n))^3.

PROG

(PARI) a(n)=sum(i=1, n, bigomega(i)==4)

(PARI) a(n)=my(j, s); forprime(p=2, (n+.5)^(1/4), forprime(q=p, (n/p+.5)^(1/3), j=primepi(q)-2; forprime(r=q, sqrtint(n\(p*q)), s+=primepi(n\(p*q*r))-j++))); s \\ Charles R Greathouse IV, Mar 21 2012

CROSSREFS

Cf. A072000, A072114.

Sequence in context: A071701 A064459 A279758 * A094382 A146167 A103380

Adjacent sequences:  A082993 A082994 A082995 * A082997 A082998 A082999

KEYWORD

nonn,easy

AUTHOR

Benoit Cloitre, May 30 2003

STATUS

approved

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Last modified May 23 23:53 EDT 2017. Contains 286937 sequences.