A325125 Number of simple graphs on n unlabeled nodes with exactly 2 endpoints (nodes of degree 1).

0, 1, 2, 3, 7, 25, 126, 968, 11752, 240615, 8529544, 534168034, 59794030430, 12082250628276, 4446033336286696, 3002923486915259644, 3748228681583390913192, 8696890616699403375722774, 37700601714008218904828607832, 306674623374061557486512987705844

Offset

1,3

Links

Andrew Howroyd, Table of n, a(n) for n = 1..50

Crossrefs

Column k=2 of A327371.

Cf. A277073 (labeled case), A325115.

Sequence in context: A095910 A074189 A301317 * A091230 A063852 A301519

Adjacent sequences: A325122 A325123 A325124 * A325126 A325127 A325128

Keyword

nonn

Author

Andrew Howroyd, Sep 04 2019

Extensions

Terms a(11) and beyond from Andrew Howroyd, Feb 02 2021

Status

approved