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A294728
Number of Q graphs with 2*n vertices symmetrical about a distinguished edge.
1
0, 0, 0, 1, 1, 6, 7, 37, 47, 242, 324, 1658, 2300, 11764, 16741, 85741, 124383, 638250, 939880, 4832446, 7202214, 37101556, 55842670, 288180066, 437325262, 2260516372, 3454370352, 17881862308, 27489383818, 142491830992, 220185726817
OFFSET
1,6
LINKS
R. C. Read, On the enumeration of a class of plane multigraphs, Aequat. Math. 31 (1986) no 1, 47-63.
FORMULA
G.f.: H(x) * (B(x^2) - x^2) where H(x) is the g.f. for A007165 and B(x) is the g.f. for A003168.
CROSSREFS
Sequence in context: A027021 A013627 A248850 * A219212 A301904 A152119
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Nov 07 2017
STATUS
approved