A289157 Number of unlabeled connected loopless multigraphs with n nodes of degree 4 or less.

1, 1, 4, 9, 37, 146, 772, 4449, 30307, 228605, 1921464, 17652327, 176162548, 1893738334, 21806975279, 267636988052, 3486370839295, 48029272657002, 697542580286159, 10649954607360119, 170508064788069346, 2856122791685125616, 49951625299057923405

Offset

0,3

Links

Table of n, a(n) for n=0..22.

Prog

(nauty/bash) geng -c -D4 ${n} -q | multig -D4 -u

Crossrefs

Column k=4 of A334546.

Cf. A121941 (single edges only), A134818 (with no more than triple edges), A289158 (with no more than double edges).

Cf. A243391 (degree 3 or less).

Sequence in context: A066924 A251689 A249101 * A149146 A149147 A149148

Adjacent sequences: A289154 A289155 A289156 * A289158 A289159 A289160

Keyword

nonn

Author

Natan Arie Consigli, Jul 04 2017

Extensions

a(18)-a(22) from Andrew Howroyd, Mar 20 2020

Status

approved