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

Offset: 1

Author

Vincenzo Librandi, Jan 18 2009

Keywords

• nonn
• easy

Examples

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

Links

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

Crossrefs

Cf. A154616.

Subsequence of A007528.

Programs

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 *)

Extensions

Extended by Emeric Deutsch, Jan 20 2009

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