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A082996
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a(n) = card{ x <= n : bigomega(x) = 4 }.
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2
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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)
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OFFSET
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1,24
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LINKS
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Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
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FORMULA
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a(n) ~ (1/6)*(n/log(n))*log(log(n))^3
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PROG
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(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
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CROSSREFS
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Cf. A072000, A072114.
Sequence in context: A111855 A071701 A064459 * A094382 A146167 A103380
Adjacent sequences: A082993 A082994 A082995 * A082997 A082998 A082999
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KEYWORD
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nonn,easy,changed
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AUTHOR
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Benoit Cloitre, May 30 2003
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STATUS
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approved
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