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A320994
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Number of connected point-self-dual nets with 2n nodes.
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1
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1, 2, 37, 3264, 1798306, 7066174625, 208496688495494, 47481277563116098111, 85161165189313899034899294, 1221965295353715648352925546245057, 142024241427456183309163988600775633635361, 135056692113925953789612785828652550808044930178235
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OFFSET
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0,2
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LINKS
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Andrew Howroyd, Table of n, a(n) for n = 0..40
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. 274.
Andrew Howroyd, PARI Program
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FORMULA
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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 A004105. - Andrew Howroyd, Jan 27 2020
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PROG
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(PARI) \\ See link for program.
A320994seq(15) \\ Andrew Howroyd, Jan 27 2020
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CROSSREFS
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Cf. A004103 (nets), A004105 (point-self-dual on 2n nodes), A320489 (connected nets).
Sequence in context: A234971 A139108 A165697 * A083189 A145798 A110762
Adjacent sequences: A320991 A320992 A320993 * A320995 A320996 A320997
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Oct 26 2018
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EXTENSIONS
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a(0)=1 prepended and terms a(7) and beyond from Andrew Howroyd, Jan 26 2020
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STATUS
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approved
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