A154619 Primes of the form (4k^2 + 4k - 5)/5.

23, 71, 167, 191, 479, 743, 1583, 2039, 2927, 3863, 5711, 6551, 7919, 9767, 10487, 11423, 15791, 16703, 18119, 21647, 21911, 24359, 27527, 32159, 35111, 35447, 38543, 43991, 45887, 46271, 52223, 54287, 55967, 60719, 67511, 69383, 76631

Offset

1,1

Comments

The numbers k that generate integers of the form (4k^2 + 4k - 5)/5 are in A047208. The primes are generated by the subset k = 5, 9, 14, 15, 24, 30, ... of these. - R. J. Mathar, Jan 25 2009

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Maple

a := proc (n) if type((4/5)*n^2+(4/5)*n-1, integer) = true and isprime((4/5)*n^2+(4/5)*n-1) = true then (4/5)*n^2+(4/5)*n-1 else end if end proc: seq(a(n), n = 1 .. 340); # Emeric Deutsch, Jan 21 2009

Mathematica

Select[Table[(4n^2+4n-5)/5, {n, 3, 200}], PrimeQ] (* Vincenzo Librandi, Jul 23 2012 *)

Crossrefs

Cf. A028880.

Sequence in context: A188831 A183012 A319052 * A142405 A139962 A248877

Adjacent sequences: A154616 A154617 A154618 * A154620 A154621 A154622

Keyword

nonn,easy

Author

Vincenzo Librandi, Jan 16 2009

Extensions

Definition corrected and more terms from R. J. Mathar and Omar E. Pol, Jan 24 2009

Extended by Emeric Deutsch, Jan 21 2009

Status

approved