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A320995
Number of connected self-dual nets with 2n nodes.
1
1, 0, 5, 136, 24162, 29488085, 286615837574, 21717610066598371, 12980514969049888065118, 62082684164458190567999459967, 2405195234525224724112302276711929089, 762399076229936058613587754015434541854738381
OFFSET
0,3
LINKS
Edward A. Bender and E. Rodney Canfield, Enumeration of connected invariant graphs, Journal of Combinatorial Theory, Series B 34.3 (1983): 268-278. See p. 275.
Andrew Howroyd, PARI Program
FORMULA
a(2*n-1) = b(2*n-1) - A320489(2*n-1)/2, a(2*n) = b(2*n) - (A320489(2*n)-a(n))/2 where b is the Inverse Euler transform of A004107. - Andrew Howroyd, Jan 27 2020
PROG
(PARI) \\ See link for program.
A320995seq(15) \\ Andrew Howroyd, Jan 27 2020
CROSSREFS
Cf. A004103 (not necessarily connected nets), A004107 (self-dual), A320489 (connected nets).
Sequence in context: A208867 A094808 A367528 * A061453 A215958 A216337
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 26 2018
EXTENSIONS
a(0)=1 prepended and terms a(7) and beyond from Andrew Howroyd, Jan 26 2020
STATUS
approved