OFFSET
1,1
COMMENTS
There is the sequence SemiprimePi for semiprimes ==1 (mod 4) which grows as 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 8, 8, 9, 9, 10, 10,... and another SemiprimePi for == 3 (mod 4) which grows as 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3, 3, 4, 5, 5,... We watch the difference 0, 0, -1, -1, -1, 0, -1, -1, -2, -2, -3, -3, -2,.. and note the semiprimes where this difference becomes >0.
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..4960 (terms < 2*10^9)
K. Ford, J. Sneed, Chebyshev's bias for products of two primes, Exper. Math. 19 (4) (2010) 385-398
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Oct 07 2011
STATUS
approved