This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A325079 #15 Apr 12 2019 18:53:31 %S A325079 71,251,311,631,661,691,751,881,1061,1171,1181,1321,1571,1721,1741, %T A325079 1901,1951,2341,2531,2621,2671,2711,2731,2971,3191,3271,3371,3491, %U A325079 3631,3701,3851,3881,4481,4591,4651,5261,5471,5501,5531,5581,5641,5701,5861,6121,6271 %N A325079 Prime numbers congruent to 1, 16, 26, 31 or 36 modulo 55 representable by both x^2 + x*y + 14*y^2 and x^2 + x*y + 69*y^2. %C A325079 Brink showed that prime numbers congruent to 1, 16, 26, 31 or 36 modulo 55 are representable by both or neither of the quadratic forms x^2 + x*y + 14*y^2 and x^2 + x*y + 69*y^2. This sequence corresponds to those representable by both, and A325080 corresponds to those representable by neither. %H A325079 David Brink, <a href="https://doi.org/10.1016/j.jnt.2008.04.007">Five peculiar theorems on simultaneous representation of primes by quadratic forms</a>, Journal of Number Theory 129(2) (2009), 464-468, doi:10.1016/j.jnt.2008.04.007, MR 2473893. %H A325079 Rémy Sigrist, <a href="/A325079/a325079.gp.txt">PARI program for A325079</a> %H A325079 Wikipedia, <a href="https://en.wikipedia.org/wiki/Kaplansky%27s_theorem_on_quadratic_forms">Kaplansky's theorem on quadratic forms</a> %e A325079 Regarding 881: %e A325079 - 881 is a prime number, %e A325079 - 881 = 16*55 + 1, %e A325079 - 881 = 3^2 + 3*(-8) + 14*(-8)^2 = 28^2 + 28*1 + 69*1^2, %e A325079 - hence 881 belongs to this sequence. %o A325079 (PARI) See Links section. %Y A325079 See A325067 for similar results. %Y A325079 Cf. A325080. %K A325079 nonn %O A325079 1,1 %A A325079 _Rémy Sigrist_, Mar 28 2019