A091374 Number of numbers <= n having fewer prime factors than the value of their smallest prime factor.

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.

Links

Table of n, a(n) for n=1..74.

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

Cf. A091377, A091371.

Sequence in context: A254531 A005410 A120835 * A266977 A370457 A361234

Adjacent sequences: A091371 A091372 A091373 * A091375 A091376 A091377

Keyword

nonn

Author

Reinhard Zumkeller, Jan 04 2004

Status

approved