A241841 Number of simple connected graphs on n nodes that are not trees.

0, 0, 1, 4, 18, 106, 842, 11094, 261033, 11716465, 1006700330, 164059829925, 50335907867918, 29003487462844902, 31397381142761234219, 63969560113225176156957, 245871831682084026519479939, 1787331725248899088890200452713, 24636021429399867655322650759363689

Offset

1,4

Links

Georg Fischer, Table of n, a(n) for n = 1..40

Travis Hoppe and Anna Petrone, Encyclopedia of Finite Graphs

T. Hoppe and A. Petrone, Integer sequence discovery from small graphs, arXiv preprint arXiv:1408.3644 [math.CO], 2014.

T. Hoppe and A. Petrone, Integer sequence discovery from small graphs, Discr. Appl. Math. 201 (2016) 172-181.

Eric Weisstein's World of Mathematics, Connected Graph

Eric Weisstein's World of Mathematics, Cyclic Graph

Eric Weisstein's World of Mathematics, Tree

Formula

a(n) = A001349(n) - A000055(n).

Crossrefs

Cf. A000055, A001349, A286743, A306003.

Sequence in context: A020114 A354015 A009597 * A241842 A306003 A214840

Adjacent sequences: A241838 A241839 A241840 * A241842 A241843 A241844

Keyword

nonn

Author

Travis Hoppe and Anna Petrone, Apr 29 2014

Status

approved