login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A153041 Numbers n >=10 such that 2*n-19 is not a prime. 4
10, 14, 17, 20, 22, 23, 26, 27, 29, 32, 34, 35, 37, 38, 41, 42, 44, 47, 48, 50, 52, 53, 55, 56, 57, 59, 62, 65, 67, 68, 69, 70, 71, 72, 74, 76, 77, 80, 81, 82, 83, 86, 87, 89, 90, 92, 94, 95, 97, 98, 101, 102, 103, 104 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

One more than associated values in A153051, two more than A153047. - R. J. Mathar, Jan 05 2011

The terms after a(1) are the values of 2*h*k + k + h + 10, where h and k are positive integers.- Vincenzo Librandi, Jan 19 2013

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[10, 200], !PrimeQ[2 # - 19] &] (* Vincenzo Librandi, Jan 19 2013 *)

PROG

(MAGMA) [n: n in [10..150] | not IsPrime(2*n - 19)]; // Vincenzo Librandi, Jan 19 2013

CROSSREFS

Cf. A097932, A155704.

Numbers n such that 2n-k is not prime: A104275 (k=1), A153043 (k=3), A153040 (k=5), A153039 (k=7), A153044 (k=9), A153045 (k=11), A153049 (k=13), A153047 (k=15), A153051 (k=17), A153041 (k=19).

Similar sequence listed also in A089559, A153144.

Sequence in context: A055197 A116610 A289698 * A256471 A250403 A096851

Adjacent sequences:  A153038 A153039 A153040 * A153042 A153043 A153044

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Dec 17 2008

EXTENSIONS

Edited by N. J. A. Sloane, Jun 22 2010

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 January 17 20:36 EST 2020. Contains 330987 sequences. (Running on oeis4.)