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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A153086 Numbers n such that 4*n+7 is not prime 1
2, 5, 7, 8, 11, 12, 14, 17, 20, 21, 22, 23, 26, 27, 28, 29, 32, 34, 35, 37, 38, 41, 42, 44, 45, 47, 49, 50, 52, 53, 56, 57, 59, 60, 62, 63, 65, 67, 68, 70, 71, 72, 73, 74, 77, 78, 79, 80, 82, 83, 84, 86, 87, 89, 91, 92, 95, 96, 97, 98, 99, 100, 101, 102, 104, 105, 107 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

*;

2, *;

*, 7, *;

5, *, 14, *;

*, 12, *, 23, *;

8, *, 21, *, 34, *;

*, 17, *, 32, *, 47, *; etc.

where * marks the non-integer values of (2*n*k + k + n - 3)/2 with n >= k >= 1. - Vincenzo Librandi, Nov 21 2012

MATHEMATICA

Select[Range[200], !PrimeQ[4# + 7] &] (* Vincenzo Librandi, Nov 21 2012 *)

PROG

(MAGMA) [n: n in [1..120] | not IsPrime(4*n + 7)]; // Vincenzo Librandi, Nov 21 2012

CROSSREFS

Cf. A089986, A153053.

Sequence in context: A299232 A153083 A140592 * A032784 A277266 A047268

Adjacent sequences:  A153083 A153084 A153085 * A153087 A153088 A153089

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Dec 18 2008

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 24 01:05 EST 2020. Contains 331178 sequences. (Running on oeis4.)