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A091374
Number of numbers <= n having fewer prime factors than the value of their smallest prime factor.
4
1, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 30, 30, 30, 30, 31, 31, 32, 32, 33, 33, 34, 34, 35, 35
OFFSET
1,2
COMMENTS
a(n) = #{m: A001222(m) < A020639(m), m<=n};
A091372(n) + A091373(n) + a(n) = n.
PROG
(PARI) isok(n) = {my(f=factor(n)); (#f~ == 0) || (bigomega(n) < f[1, 1]); }
a(n) = sum(k=1, n, isok(k)); \\ Michel Marcus, Feb 05 2016
CROSSREFS
Sequence in context: A254531 A005410 A120835 * A266977 A370457 A361234
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jan 04 2004
STATUS
approved