

A162294


Numbers k such that k^3k^2k1 is prime.


4



4, 6, 8, 12, 16, 22, 28, 34, 44, 50, 54, 56, 58, 76, 78, 88, 110, 112, 118, 134, 138, 156, 162, 166, 168, 170, 188, 190, 200, 204, 208, 210, 226, 230, 236, 244, 250, 268, 274, 302, 310, 314, 322, 324, 340, 344, 356, 364, 368, 378, 382, 390, 398, 400, 420, 424
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OFFSET

1,1


LINKS

Ivan Neretin, Table of n, a(n) for n = 1..10000


FORMULA

k^3k^2k1 = A162295(n), where k=a(n).
Sum_{i=1..n} a(i) = Sum_{i=1..n} i * ( pi(i^3  i^2  i  1)  pi(i^3  i^2  i  2) ).  Wesley Ivan Hurt, May 24 2013


EXAMPLE

k=4 is in the sequence because 4^34^241=43 is prime.
k=6 is in the sequence because 6^36^261=173 is prime.


MATHEMATICA

lst={}; Do[p=n^3n^2n1; If[PrimeQ[p], AppendTo[lst, n]], {n, 2, 6!}]; lst


CROSSREFS

Cf. A087908, A111501, A162291, A162293, A162295 (corresponding primes).
Sequence in context: A062554 A020225 A310663 * A344994 A211026 A090989
Adjacent sequences: A162291 A162292 A162293 * A162295 A162296 A162297


KEYWORD

nonn


AUTHOR

Vladimir Joseph Stephan Orlovsky, Jun 30 2009


EXTENSIONS

Edited by R. J. Mathar, Jul 02 2009


STATUS

approved



