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A175283
Numbers k with the property that k and k^2 + 3k+9 are primes.
1
2, 7, 11, 17, 23, 29, 31, 37, 43, 73, 101, 107, 127, 163, 179, 197, 239, 277, 281, 317, 331, 359, 367, 421, 457, 463, 487, 541, 569, 613, 617, 619, 661, 709, 739, 773, 787, 809, 823, 877, 941, 947, 953, 991, 1019, 1031, 1033, 1039, 1051, 1087, 1163, 1187
OFFSET
1,1
COMMENTS
Or, primes in A175282.
MATHEMATICA
Select[Prime[Range[400]], PrimeQ[ #^2+3*#+9]&]
PROG
(Magma) [ n: n in [0..1250] | IsPrime(n) and IsPrime(n^2+3*n+9)] // Vincenzo Librandi, Jan 30 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Mar 21 2010
STATUS
approved