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 A139508 Primes of the form x^2 + 28x*y + y^2 for x and y nonnegative. 1
 61, 181, 601, 829, 1069, 1249, 1381, 1429, 1609, 1621, 1741, 2029, 2089, 2161, 2341, 2389, 2521, 3121, 3169, 3181, 3301, 3709, 3769, 4021, 4261, 4549, 4729, 4801, 4861, 4969, 5209, 5281, 5521, 5581, 5641, 5749, 5821, 6301, 6361, 6421, 6529, 6709, 6829 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS In base 12, the sequence is 51, 131, 421, 591, 751, 881, 971, 9E1, E21, E31, 1011, 1211, 1261, 1301, 1431, 1471, 1561, 1981, 1X01, 1X11, 1XE1, 2191, 2221, 23E1, 2571, 2771, 28X1, 2941, 2991, 2X61, 3021, 3081, 3241, 3291, 3321, 33E1, 3451, 3791, 3821, 3871, 3941, 3X71, 3E51, where X is 10 and E is 11. Moreover, the discriminant is 550. - Walter Kehowski, Jun 01 2008 LINKS Table of n, a(n) for n=1..43. N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references) MATHEMATICA a = {}; w = 28; 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*) CROSSREFS Cf. A139489, A007645, A068228, A007519, A033212, A033212, A107152, A107008, A033215, A107145, A139490, A139491. Sequence in context: A088955 A087870 A121513 * A364716 A245865 A357780 Adjacent sequences: A139505 A139506 A139507 * A139509 A139510 A139511 KEYWORD nonn AUTHOR Artur Jasinski, Apr 24 2008 STATUS approved

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Last modified December 7 12:41 EST 2023. Contains 367656 sequences. (Running on oeis4.)