A329182 Negative discriminants with form class group isomorphic to C_2 X C_2 (negated).

84, 96, 120, 132, 160, 168, 180, 192, 195, 228, 240, 280, 288, 312, 315, 340, 352, 372, 408, 435, 448, 483, 520, 532, 555, 595, 627, 708, 715, 760, 795, 928, 1012, 1435

Offset

1,1

Comments

This sequence is finite and this is the full list.

Equivalently, negative discriminants of orders whose class group is isomorphic to C_2 X C_2 (negated). - Jianing Song, May 17 2021

Links

Table of n, a(n) for n=1..34.

Rick L. Shepherd, Binary quadratic forms and genus theory, Master of Arts Thesis, University of North Carolina at Greensboro, 2013

Prog

(PARI) isA329182(d) = (d>0) && ((d%4==0)||(d%4==3)) && quadclassunit(-d)[2]==[2, 2] \\ Jianing Song, May 17 2021

Crossrefs

Cf. A133675 (negative discriminants with form class group isomorphic to the trivial group), A322710 (isomorphic to C_2), A328825 (isomorphic to C_3), this sequence (isomorphic to C_2 X C_2), A330219 (isomorphic to C_4).

The fundamental terms are listed in A192322. Cf. also A013658.

Sequence in context: A045569 A219183 A289218 * A113931 A352230 A214866

Adjacent sequences: A329179 A329180 A329181 * A329183 A329184 A329185

Keyword

nonn,fini,full

Author

Jianing Song, Dec 05 2019

Status

approved