

A067026


(Prime(n)#  4)/2 is prime, where x# is the primorial A034386(x).


24



3, 4, 5, 6, 7, 8, 9, 11, 13, 16, 20, 27, 39, 83, 103, 122, 129, 145, 279, 393, 608, 798, 929, 1164, 1266, 1491, 2043, 3276, 3426, 7119, 15711, 18424
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OFFSET

1,1


COMMENTS

n such that A002110(n)/2  2 is prime.
a(33) > 25000.  Robert Price, Sep 29 2017


LINKS

Table of n, a(n) for n=1..32.


MATHEMATICA

p = 1; Do[p = p*Prime[n]; If[PrimeQ[(p  4)/2], Print[n]], {n, 1, 400} ]
Flatten[Position[Rest[FoldList[Times, 1, Prime[Range[2100]]]], _?(PrimeQ[(#4)/2]&)]] (* Harvey P. Dale, Nov 22 2014 *)


CROSSREFS

Cf. A002110, A067024, A067027.
Sequence in context: A189080 A039113 A130399 * A096829 A265126 A039120
Adjacent sequences: A067023 A067024 A067025 * A067027 A067028 A067029


KEYWORD

nonn


AUTHOR

Labos Elemer, Dec 29 2001


EXTENSIONS

More terms from Robert G. Wilson v, Dec 30 2001
a(21)a(27) from Ray Chandler, Jun 16 2013
a(28)a(32) from Robert Price, Sep 29 2017


STATUS

approved



