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A139501
Primes of the form x^2 + 21x*y + y^2 for x and y nonnegative.
1
23, 47, 73, 101, 131, 139, 163, 197, 233, 239, 271, 277, 311, 347, 349, 353, 397, 443, 461, 463, 491, 499, 541, 577, 587, 593, 647, 653, 691, 719, 739, 761, 809, 821, 823, 853, 859, 883, 929, 947, 967, 997, 1013, 1051, 1061, 1087, 1151, 1163, 1223, 1277
OFFSET
1,1
LINKS
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
MATHEMATICA
a = {}; w = 21; k = 1; Do[Do[If[PrimeQ[n^2 + w*n*m + k*m^2], AppendTo[a, n^2 + w*n*m + k*m^2]], {n, m, 400}], {m, 1, 400}]; Union[a] (*Artur Jasinski*)
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 24 2008
STATUS
approved