A344408 Positive discriminants of orders with class number 2.

40, 60, 65, 85, 96, 104, 105, 120, 136, 140, 156, 160, 165, 168, 185, 192, 200, 204, 205, 220, 221, 224, 232, 240, 252, 260, 264, 265, 273, 280, 285, 288, 296, 300, 305, 312, 320, 325, 336, 340, 345, 348, 352, 357, 360, 364, 365, 377, 380, 384, 385, 408

Offset: 1

Author

Jianing Song, May 17 2021

Keywords

• nonn

Comments

Also positive discriminants of orders with class group isomorphic to C_2.

The fundamental terms are listed in A094619.

Links

• Jianing Song, Table of n, a(n) for n = 1..10001

Crossrefs

Cf. A133315 (positive discriminants of orders with class number 1), this sequence (class number 2), A344409 (class number 3).

Cf. A322710 (the negative discriminant case), A094619.

Programs

PARI

isA344408(d) = (d>0) && !issquare(d) && ((d%4==0)||(d%4==1)) && quadclassunit(d)[2]==[2]