A118859 Numbers k such that k-1, k+1, 2*k-1, 2*k+1, 3*k-1 and 3*k+1 are primes.

6, 53550, 420420, 422310, 1624350, 2130240, 3399900, 5199810, 5246010, 6549270, 7384440, 7775880, 9516570, 9565710, 10430280, 11845260, 13207950, 14562870, 14619990, 18747960, 20099940, 21596820, 21968100, 24358950, 24610740, 26916120, 28359240, 30838080

Offset

1,1

Links

Table of n, a(n) for n=1..28.

Example

6 is there because 5, 7, 11, 13, 17, 19 are all prime.

Mathematica

Select[Range[25*10^6], AllTrue[Flatten[{#+{1, -1}, 2#+{1, -1}, 3#+{1, -1}}], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 13 2016 *)

Crossrefs

Cf. A014574, A066388, A118860, A349321, A348348.

Sequence in context: A353033 A289391 A295817 * A323725 A259162 A076913

Adjacent sequences: A118856 A118857 A118858 * A118860 A118861 A118862

Keyword

nonn

Author

Labos Elemer, May 03 2006

Extensions

Edited by Don Reble, May 16 2006

a(26)-a(28) from Jon E. Schoenfield, Dec 07 2021

Status

approved