A392443 Number of finite regions in a complete bipartite graph where the vertices in the two parts are placed on opposite sides of a parabola at integer y coordinates y = 1, 2, ...n.

0, 2, 13, 44, 115, 243, 470, 819, 1337, 2071, 3090, 4412, 6163, 8367, 11112, 14480, 18607, 23496, 29363, 36203, 44203, 53475, 64166, 76282, 90096, 105734, 123311, 142964, 164971, 189283, 216342, 246095, 278861, 314815, 354105, 396808, 443535, 494207, 549076

Offset

1,2

Links

Table of n, a(n) for n=1..39.

Scott R. Shannon, Illustration for n = 2.

Scott R. Shannon, Illustration for n = 3.

Scott R. Shannon, Illustration for n = 4.

Scott R. Shannon, Illustration for n = 5.

Scott R. Shannon, Illustration for n = 6.

Scott R. Shannon, Illustration for n = 10.

Formula

a(n) = A392444(n) - A392442(n) + 1 by Euler's formula.

Crossrefs

Cf. A392442 (vertices), A392444 (edges), A392426 (integer x), A290131.

Sequence in context: A308731 A392426 A025194 * A084156 A002534 A212501

Adjacent sequences: A392440 A392441 A392442 * A392444 A392445 A392446

Keyword

nonn

Author

Scott R. Shannon, Jan 12 2026

Status

approved