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Revision History for A034428

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A034428

E.g.f.: 1 - (1-x)*(tan(x) + sec(x)).
(history; published version)

#62 by N. J. A. Sloane at Tue Aug 06 21:36:16 EDT 2024

STATUS

proposed

approved

#61 by Jason Yuen at Tue Aug 06 21:34:55 EDT 2024

STATUS

editing

proposed

#60 by Jason Yuen at Tue Aug 06 21:34:41 EDT 2024

PROG

(PARI) a(n)=n!*polcoeff(1-(1-x)*(tan(x+x*O(x^n))+1/cos(x+x*O(x^n))), n)

STATUS

approved

editing

#59 by Peter Luschny at Sat Jun 11 11:41:36 EDT 2022

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proposed

approved

#58 by Michel Marcus at Sat Jun 11 09:15:13 EDT 2022

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editing

proposed

#57 by Michel Marcus at Sat Jun 11 09:15:02 EDT 2022

COMMENTS

Also: number of permutations on n elements having the descent pattern: up, up, down, up, down, ...; a(n) = n * E_{n-1} - E_{n} where E_{n} denotes the Euler numbers, see sequence A000111. - _Richard Ehrenborg, _, Feb 12 2002

STATUS

approved

editing

#56 by Michel Marcus at Fri Feb 26 02:42:49 EST 2021

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reviewed

approved

#55 by Joerg Arndt at Fri Feb 26 01:51:09 EST 2021

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proposed

reviewed

#54 by Michel Marcus at Fri Feb 26 00:26:14 EST 2021

STATUS

editing

proposed

#53 by Michel Marcus at Fri Feb 26 00:26:11 EST 2021

LINKS

Miklós Bóna, and István Mező, <a href="https://doi.org/10.37236/7731">Limiting Probabilities for Vertices of a Given Rank in 1-2 Trees</a>, The Electronic Journal of Combinatorics (2019) Vol. 26, No. 3, P#3.41.

STATUS

proposed

editing