# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a325088 Showing 1-1 of 1 %I A325088 #16 Apr 12 2019 08:24:43 %S A325088 241,409,1201,1609,2089,2161,3049,3121,3529,4561,4729,4969,5281,6481, %T A325088 6961,7129,7369,7681,8089,8161,9049,11689,12241,12721,12889,13441, %U A325088 13921,14401,16249,17449,17929,19441,19609,19681,20161,20641,20809,21121,21841,23041 %N A325088 Prime numbers congruent to 1 or 169 modulo 240 representable neither by x^2 + 150*y^2 nor by x^2 + 960*y^2. %C A325088 Brink showed that prime numbers congruent to 1 or 169 modulo 240 are representable by both or neither of the quadratic forms x^2 + 150*y^2 and x^2 + 960*y^2. A325087 corresponds to those representable by both, and this sequence corresponds to those representable by neither. %H A325088 David Brink, Five peculiar theorems on simultaneous representation of primes by quadratic forms, Journal of Number Theory 129(2) (2009), 464-468, doi:10.1016/j.jnt.2008.04.007, MR 2473893. %H A325088 Rémy Sigrist, PARI program for A325088 %H A325088 Wikipedia, Kaplansky's theorem on quadratic forms %e A325088 Regarding 241: %e A325088 - 241 is a prime number, %e A325088 - 241 = 1*240 + 1, %e A325088 - 241 is neither representable by x^2 + 150*y^2 nor by x^2 + 960*y^2, %e A325088 - hence 241 belongs to this sequence. %o A325088 (PARI) See Links section. %Y A325088 See A325067 for similar results. %Y A325088 Cf. A325087. %K A325088 nonn %O A325088 1,1 %A A325088 _Rémy Sigrist_, Mar 28 2019 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE