A392427 Number of edges in a complete bipartite graph where the vertices in the two parts are placed on opposite sides of a parabola at integer x coordinates |x| = 1, 2, ...n.

1, 6, 27, 85, 210, 437, 836, 1442, 2347, 3634, 5351, 7700, 10685, 14500, 19183, 24914, 31899, 40220, 50263, 62099, 75754, 91655, 109810, 131001, 154733, 181506, 211901, 245359, 282708, 324803, 371712, 423507, 479872, 542141, 609946, 683574, 764275, 852370

Offset

1,2

Comments

See A392425 and A392426 for illustrations of the graphs.

Links

Table of n, a(n) for n=1..38.

Formula

a(n) = A392425(n) + A392426(n) - 1 by Euler's formula.

Crossrefs

Cf. A392425 (vertices), A392426 (regions), A392444 (integer y), A290132.

Sequence in context: A124089 A250283 A100188 * A392444 A131985 A125196

Adjacent sequences: A392424 A392425 A392426 * A392428 A392429 A392430

Keyword

nonn

Author

Scott R. Shannon, Jan 11 2026

Status

approved