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Prime determinants of forms with class number > 2.
1

%I #11 Feb 17 2021 04:19:45

%S 79,223,359,439,443,499,659,727,839,1087,1091,1171,1223,1327,1367,

%T 1523,1567,1627,1787,1811,1847,1907,1987,2027,2099,2143,2207,2251,

%U 2399,2459,2467,2543,2659,2711,2971,3023,3163,3251,3391,3719,3739,3803,3967,4139,4159,4271

%N Prime determinants of forms with class number > 2.

%C Also primes p == 3 (mod 4) such that Z[sqrt(p)] = Z[x]/(x^2 - p) is not a unique factorization domain (or equivalently, not a principal ideal domain). - _Jianing Song_, Feb 17 2021

%H M. Suryanarayana, <a href="https://www.ias.ac.in/article/fulltext/seca/002/02/0178-0179">Positive determinants of binary quadratic forms whose class-number is 2</a>, Proceedings of the Indian Academy of Sciences. Section A, 2 (1935), 178-179.

%o (PARI) isA260335(p) = isprime(p) && (p%4==3) && quadclassunit(4*p)[1] > 1 \\ _Jianing Song_, Feb 17 2021

%Y Cf. A002052.

%K nonn,more

%O 1,1

%A _N. J. A. Sloane_, Jul 27 2015

%E More terms from _Jianing Song_, Feb 17 2021