[seqfan] inverse Euler transforms needed
Brendan McKay
Brendan.McKay at anu.edu.au
Mon Mar 12 01:50:48 CET 2018
Hi Seqfans, I have just extended four sequences of graph counts.
Since these graph classes are closed under disjoint union, the
corresponding sequence of connected graph counts can be obtained using
an inverse euler transform (but don't take my word for it).
Can someone with more spare time on their hands than I have please
extend the connected graph counts? Some cross-referencing between the
two sequences in each pair is missing too.
The sequences are:
Graphs without 3-cycles or 4-cycles: A006787->A126757
Squarefree bipartite graphs: A138347->seems not to be present,
starts 1,1,1,2,3,7,12,30,64,177,457,1403
Graphs without 4-cycles: A006786->A077269
Perfect graphs: A052431->A052433
Thanks, Brendan.
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