login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A196937 Semiprimes at which the Chebyshev bias of semiprimes == 3 (mod 4) and == 1 (mod 4) becomes positive. 1
26747, 26791, 26799, 26935, 611287, 611319, 611327, 611335, 611383, 620107, 620119, 620219, 620859, 620899, 638291, 638311, 638351, 638647, 638659, 638671, 638691, 638779, 639071, 652003, 652027, 652187, 652551, 652583, 652603, 652735, 652751, 653047, 653059, 653063, 653071, 653095, 653119, 653215 (list; graph; refs; listen; history; text; internal format)
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

Cf. A108181, A080774.

Sequence in context: A229592 A046710 A251303 * A253292 A253162 A185774

Adjacent sequences:  A196934 A196935 A196936 * A196938 A196939 A196940

KEYWORD

nonn

AUTHOR

R. J. Mathar, Oct 07 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 18 17:13 EDT 2019. Contains 328186 sequences. (Running on oeis4.)