A361454 Number of 4-regular multigraphs on n unlabeled nodes with 4 external legs, loops allowed.

1, 4, 17, 78, 360, 1835, 10168, 62271, 419701, 3107800, 25108419, 219982357, 2076785950, 21011123423, 226708386212, 2598075587529, 31509529248585, 403155101535686, 5426659537490872, 76655160760249052, 1133766220709242638, 17522418780011531368, 282452568669871514771, 4740645804610572971112

Offset

1,2

Links

Table of n, a(n) for n=1..24.

Crossrefs

Cf. A129429, A361698 (connected).

Sequence in context: A005494 A257072 A193782 * A364030 A053486 A151249

Adjacent sequences: A361451 A361452 A361453 * A361455 A361456 A361457

Keyword

nonn

Author

Andrew Howroyd, Mar 21 2023

Status

approved