[seqfan] labeled digraphs in A214398
Richard J. Mathar
mathar at mpia-hd.mpg.de
Thu Aug 3 14:16:27 CEST 2017
If we arrange the triangle http://oeis.org/A214398 such that
it becomes an array T(n,k) (read by antidiagonals) of the form
1 1 1 1 1
1 4 9 16 25 36
1 10 45 136 325 666
1 20 165 816 2925 8436
1 35 495 3876 20475 82251
1 56 1287 15504 118755 658008
1 84 3003 54264 593775 4496388
1 120 6435 170544 2629575 ...
does this count in row n and column k the
labeled digraphs with n arcs and k vertices,
allowing multi-edges and loops? So would that be
the labeled analog of http://oeis.org/A138107 ?
RJM
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