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Revision History for A006082 (Underlined text is an addition; strikethrough text is a ~~deletion~~.)
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A006082

Number of labeled projective plane trees (or "flat" trees) with n nodes.
(history; published version)

#73 by Andrey Zabolotskiy at Thu Mar 21 21:09:57 EDT 2024

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#72 by Andrey Zabolotskiy at Thu Mar 21 21:09:54 EDT 2024

PROG

\\ from David Broadhurst, Apr 06 2022, added by N. J. A. Sloane, Apr 06 2022)

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#71 by Alois P. Heinz at Mon Sep 25 15:00:33 EDT 2023

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#70 by Robert C. Lyons at Mon Sep 25 14:55:01 EDT 2023

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#69 by Robert C. Lyons at Mon Sep 25 14:54:56 EDT 2023

PROG

(PARI)

(Pari, \\ from David Broadhurst, Apr 06 2022, added by N. J. A. Sloane, Apr 06 2022)

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#68 by Vaclav Kotesovec at Wed Jun 01 05:38:58 EDT 2022

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#67 by Vaclav Kotesovec at Wed Jun 01 05:38:49 EDT 2022

FORMULA

a(n) ~ 2^(2*n-4) / (sqrt(Pi) * n^(5/2)). - Vaclav Kotesovec, Jun 01 2022

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#66 by N. J. A. Sloane at Wed Apr 06 08:17:03 EDT 2022

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#65 by N. J. A. Sloane at Wed Apr 06 08:17:00 EDT 2022

LINKS

T. S. Motzkin, <a href="http://dx.doi.org/10.1090/S0002-9904-1948-09002-4 ">Relations between hypersurface cross ratios and a combinatorial formula for partitions of a polygon, for permanent preponderance and for non-associative products</a>, Bull. Amer. Math. Soc., 54 (1948), 352-360. [The sequence is mentioned on page 355, but because of a miscalculation it is given, incorrectly, as 1, 1, 1, 2, 3, 6, 12, 25. Thanks to David Broadhurst for this information. -. _. - _N. J. A. Sloane_, Apr 06 2022]

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#64 by N. J. A. Sloane at Wed Apr 06 08:16:17 EDT 2022

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Last modified August 29 17:19 EDT 2024. Contains 375518 sequences. (Running on oeis4.)