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 A320488 Inverse Euler transform of A004104. 1
 1, 1, 0, 1, 4, 14, 65, 572, 7434, 163284, 5736792, 342169618, 33534958026, 5442700283638, 1484664947481018, 664513607618098252, 508538464299684269212, 635542752091150346032474, 1374528064543284187245552390, 4842758246111267151697826493193, 29772724415959420224886585241636839 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS The inverse Euler transform of A004104 does not give the number of connected self-dual signed graphs. The combinatorial interpretation of this sequence is that of either a connected self-dual signed graph or a pair of distinct connected signed graphs which are dual to each other (but not self-dual). - Andrew Howroyd, Jan 26 2020 LINKS Andrew Howroyd, Table of n, a(n) for n = 0..50 N. J. A. Sloane, Transforms CROSSREFS Cf. A004102, A004104, A053465, A320499. Sequence in context: A119857 A305654 A241465 * A126787 A187742 A129219 Adjacent sequences:  A320485 A320486 A320487 * A320489 A320490 A320491 KEYWORD nonn AUTHOR N. J. A. Sloane, Oct 25 2018 EXTENSIONS Definition edited by Andrew Howroyd, Jan 26 2020 STATUS approved

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Last modified September 23 09:03 EDT 2020. Contains 337298 sequences. (Running on oeis4.)