A154632 - OEIS

A154632

Odd primes p such that (4*p^2-8*p-9)/3 is a prime.

5, 17, 23, 41, 59, 71, 89, 149, 197, 233, 239, 347, 359, 401, 419, 449, 563, 683, 761, 773, 827, 887, 971, 977, 1049, 1061, 1097, 1193, 1277, 1373, 1439, 1553, 1571, 1787, 1871, 1877, 1931, 2069, 2267, 2273, 2381, 2417, 2447, 2687, 2699, 2777, 2843, 2957

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

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

EXAMPLE

For p=5, (4*p^2-8*p-9)/3 = 17; for p=149, (4*p^2-8*p-9)/3 = 29201.

MAPLE

a := proc (n) if isprime(n) = true and type((4/3)*n^2-(8/3)*n-3, integer) = true and isprime((4/3)*n^2-(8/3)*n-3) = true then n else end if end proc: seq(a(n), n = 2 .. 4000); # Emeric Deutsch, Jan 20 2009

MATHEMATICA

Select[Prime[Range[2, 500]], PrimeQ[(4 #^2 - 8 # - 9)/3] &] (* Harvey P. Dale, May 20 2012 *)

CROSSREFS

Cf. A154616.

Subsequence of A007528.

Sequence in context: A105884 A019410 A133423 * A236119 A141275 A303193

Adjacent sequences: A154629 A154630 A154631 * A154633 A154634 A154635

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Jan 18 2009

EXTENSIONS

Extended by Emeric Deutsch, Jan 20 2009

Formatting of definition clarified by Harvey P. Dale, May 20 2012

STATUS

approved