

A325073


Prime numbers congruent to 9 modulo 20 representable by x^2 + 20*y^2.


3



29, 89, 229, 349, 509, 709, 769, 809, 1009, 1049, 1109, 1229, 1249, 1289, 1409, 1549, 1669, 1709, 1789, 2029, 2069, 2089, 2389, 2729, 3049, 3089, 3169, 3329, 3389, 3469, 3529, 3929, 3989, 4049, 4229, 4289, 4549, 4649, 4729, 4789, 5009, 5209, 5669, 5689, 5849
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OFFSET

1,1


COMMENTS

Brink showed that prime numbers congruent to 9 modulo 20 are representable by exactly one of the quadratic forms x^2 + 20*y^2 or x^2 + 100*y^2. This sequence corresponds to those representable by the first form, and A325074 corresponds to those representable by the second form.


LINKS



EXAMPLE

Regarding 1009:
 1009 is a prime number,
 1009 = 50*20 + 9,
 1009 = 17^2 + 20*6^2,
 hence 1009 belongs to this sequence.


PROG

(PARI) See Links section.


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



