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A154632
Odd primes p such that (4*p^2-8*p-9)/3 is a prime.
1
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
1,1
LINKS
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
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