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