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A331113 Number of signed trees with n positive edges and n negative edges. 3
1, 1, 9, 96, 1439, 24758, 476056, 9841611, 214997756, 4900190330, 115530636036, 2800145556058, 69446136484047, 1756114394736162, 45152546920446518, 1177790435393100588, 31111743336031473800, 831007304851753985293, 22416683345590695488558, 610057933331757664054671 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The total number of nodes is 2n + 1. Trees are unrooted.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..100

FORMULA

a(n) = A302939(2*n + 1, n).

CROSSREFS

Cf. A302939, A331114.

Sequence in context: A070896 A081131 A338105 * A158489 A069636 A069621

Adjacent sequences:  A331110 A331111 A331112 * A331114 A331115 A331116

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Jan 09 2020

STATUS

approved

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Last modified May 21 05:37 EDT 2022. Contains 353889 sequences. (Running on oeis4.)