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!)
A158712 Primes p such that p1=Floor[p/2]+p is prime and p2=Ceiling[p1/2]+p1 is prime. 7
2, 5, 13, 101, 293, 421, 541, 661, 821, 1021, 1301, 1493, 2621, 3221, 3373, 3853, 5693, 5981, 6133, 6421, 6733, 7853, 8861, 8941, 9173, 9221, 9341, 9901, 10061, 10093, 10181, 10613, 15373, 16061, 16333, 16381, 16421, 17093, 18061, 18493, 19141 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..41.

MATHEMATICA

lst={}; Do[p=Prime[n]; If[PrimeQ[p=Floor[p/2]+p], If[PrimeQ[p=Ceiling[p/2]+p], AppendTo[lst, Prime[n]]]], {n, 7!}]; lst

pQ[n_]:=Module[{p1=Floor[n/2]+n}, AllTrue[{p1, Ceiling[p1/2]+p1}, PrimeQ]]; Select[Prime[Range[2500]], pQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 07 2019 *)

CROSSREFS

Cf. A158708, A158709, A158710, A158711

Sequence in context: A075737 A100843 A082101 * A090472 A120266 A230518

Adjacent sequences:  A158709 A158710 A158711 * A158713 A158714 A158715

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Mar 24 2009

EXTENSIONS

Definition corrected by Harvey P. Dale, Feb 07 2019

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 5 02:41 EDT 2020. Contains 333238 sequences. (Running on oeis4.)