A392442 Number of vertices 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.

2, 5, 15, 42, 108, 225, 443, 776, 1273, 1984, 2986, 4275, 6005, 8174, 10882, 14199, 18297, 23127, 28961, 35747, 43692, 52905, 63555, 75596, 89320, 104887, 122387, 141960, 163914, 188135, 215137, 244781, 277456, 313315, 352510, 395031, 441689, 492254, 547014

Offset

1,1

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) - A392443(n) + 1 by Euler's formula.

Crossrefs

Cf. A392443 (regions), A392444 (edges), A392425 (integer x), A331755.

Sequence in context: A006649 A379629 A392425 * A303980 A148350 A304201

Adjacent sequences: A392439 A392440 A392441 * A392443 A392444 A392445

Keyword

nonn

Author

Scott R. Shannon, Jan 12 2026

Status

approved