A361361 - OEIS

A361361

Triangle read by rows: T(n,k) is the number of bicolored cubic graphs on 2n unlabeled vertices with k vertices of the first color, n >= 0, 0 <= k <= 2*n.

1, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 5, 5, 5, 2, 2, 6, 11, 33, 48, 66, 48, 33, 11, 6, 21, 68, 257, 556, 950, 1071, 950, 556, 257, 68, 21, 94, 510, 2443, 7126, 15393, 23644, 27606, 23644, 15393, 7126, 2443, 510, 94, 540, 4712, 27682, 102122, 270957, 526783, 781292, 887305, 781292, 526783, 270957, 102122, 27682, 4712, 540

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,10

COMMENTS

Adjacent vertices may have the same color.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..440 (rows 0..20)

EXAMPLE

Triangle begins:

0, 0, 0;

1, 1, 1, 1, 1;

2, 2, 5, 5, 5, 2, 2;

6, 11, 33, 48, 66, 48, 33, 11, 6;

21, 68, 257, 556, 950, 1071, 950, 556, 257, 68, 21;

...

CROSSREFS

Columns k=0..2 are A005638, A361410, A361411.

Row sums are A361362.

Central coefficients are A361409.

Cf. A321304 (connected), A361404.

Sequence in context: A317921 A195710 A321304 * A280511 A200997 A063960

Adjacent sequences: A361358 A361359 A361360 * A361362 A361363 A361364

KEYWORD

nonn,tabf

AUTHOR

Andrew Howroyd, Mar 10 2023

STATUS

approved