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

1,1

COMMENTS

Or, primes in A175282.

LINKS

Table of n, a(n) for n=1..52.

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

Cf. A005471, A175281, A175282.

Sequence in context: A297469 A168421 A038942 * A124136 A156828 A019385

Adjacent sequences:  A175280 A175281 A175282 * A175284 A175285 A175286

KEYWORD

nonn

AUTHOR

Zak Seidov, Mar 21 2010

STATUS

approved

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Last modified June 1 19:32 EDT 2020. Contains 334762 sequences. (Running on oeis4.)