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!)
A094343 List of pairs of primes (p, q) with q - p = 4. 10
3, 7, 7, 11, 13, 17, 19, 23, 37, 41, 43, 47, 67, 71, 79, 83, 97, 101, 103, 107, 109, 113, 127, 131, 163, 167, 193, 197, 223, 227, 229, 233, 277, 281, 307, 311, 313, 317, 349, 353, 379, 383, 397, 401, 439, 443, 457, 461, 463, 467, 487, 491, 499, 503, 613, 617, 643 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The two primes p and p+4 are not necessarily consecutive primes (for that, see A111980).

The pairs are listed in order, sorted by their smallest member. - N. J. A. Sloane, Dec 27 2019

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Cousin Primes

FORMULA

a(2*n-1)=A023200(n). a(2*n)=A046132(n).

EXAMPLE

The pairs are (3,7), (7,11), (13,17), etc.

MATHEMATICA

Flatten[{#, #+4}&/@Select[Prime[Range[200]], PrimeQ[#+4]&]] (* Harvey P. Dale, Apr 13 2011 *)

PROG

(PARI) isok(n) = (isprime(n) && isprime(n+4)) || (isprime(n-4) && isprime(n)); \\ Michel Marcus, Aug 26 2013

CROSSREFS

Almost identical to A111980.

Union of A023200 and A046132.

Cf. twin primes (A001097).

See also A000040, A111981, A001097.

For a gap of 6 (which initially is very common) see A140546.

Sequence in context: A010625 A011322 A140382 * A239126 A179873 A080457

Adjacent sequences:  A094340 A094341 A094342 * A094344 A094345 A094346

KEYWORD

easy,nonn

AUTHOR

Gerard Schildberger, Jun 04 2004

EXTENSIONS

Description was corrupted up during editing; correct description restored Aug 21 2005.

a(3) = 7 added by Vincenzo Librandi, May 06 2016

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 April 22 19:11 EDT 2021. Contains 343177 sequences. (Running on oeis4.)