|
|
A339286
|
|
Total number of interior vertices in the multigraphs of all unoriented series-parallel networks with n edges.
|
|
1
|
|
|
0, 1, 4, 17, 62, 255, 1026, 4363, 18656, 81446, 357708, 1584110, 7042396, 31429998, 140626375, 630640342, 2833200433, 12748771157, 57445747751, 259170739397, 1170566884224, 5292311737901, 23949417255984, 108470668735077, 491664303153769, 2230174016940385, 10122784007130716
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,3
|
|
COMMENTS
|
See A339285 for additional details.
|
|
LINKS
|
|
|
FORMULA
|
a(n) = Sum_{k=1..n-1} k*A339285(n,k).
|
|
PROG
|
(PARI) \\ See A339285 for VertexWeighted.
seq(n)={subst(deriv(VertexWeighted(n, x, y)), y, 1)}
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|