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!)
A141592 Numbers k such that k, k + 210*1, k + 210*2, k + 210*3, k + 210*4 are averages of pairs of twin primes. 0
1308498, 3042492, 3042702, 7445310, 20031102, 31572522, 44687988, 54266292, 141208620, 182316522, 237416370, 357080022, 448436322, 611641188, 699458412, 761126028, 774997368, 794065968, 836452962, 915215592, 944958942, 1009194618, 1581935940, 1763255562, 1871007372 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

1308498 and 1308708, 1308918, 1309128, 1309338 are averages of twin primes.

3042492 and 3042702, 3042912, 3043122, 3043332 are averages of twin primes.

MATHEMATICA

q=210; lst={}; Do[If[PrimeQ[n-1]&&PrimeQ[n+1]&&PrimeQ[n+q*1-1]&& PrimeQ[n+q*1+1]&& PrimeQ[n+q*2-1]&&PrimeQ[n+q*2+1]&& PrimeQ[n+q*3-1]&& PrimeQ[n+q*3+1]&& PrimeQ[n+q*4-1]&&PrimeQ[n+q*4+1], AppendTo[lst, n]], {n, 10^8}]; lst

Select[Range[55*10^6], AllTrue[{#-1, #+1, #+209, #+211, #+419, #+421, #+629, #+631, #+839, #+841}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Aug 08 2017 *)

PROG

(MAGMA) [k:k in [1..55000000]|forall{m:m in [0, 210, 420, 630, 840]|IsPrime(k+m-1) and IsPrime(k+m+1)}]; // Marius A. Burtea, Jan 13 2020

CROSSREFS

Cf. A001097, A001359, A006512, A014574.

Sequence in context: A186138 A066702 A261731 * A234710 A116495 A179584

Adjacent sequences:  A141589 A141590 A141591 * A141593 A141594 A141595

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Aug 20 2008

EXTENSIONS

Edited by N. J. A. Sloane, Aug 24 2008

a(9)-a(25) from Amiram Eldar, Jan 13 2020

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 September 16 21:28 EDT 2021. Contains 347473 sequences. (Running on oeis4.)