The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A152497 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A152497

1/3 of the number of permutations of 2 indistinguishable copies of 1..n with exactly 5 local maxima.
(history; published version)

#6 by Susanna Cuyler at Tue May 12 12:54:54 EDT 2020

STATUS

proposed

approved

#5 by Andrew Howroyd at Tue May 12 12:41:51 EDT 2020

STATUS

editing

proposed

#4 by Andrew Howroyd at Tue May 12 12:05:46 EDT 2020

DATA

0, 0, 0, 0, 2464, 744881, 104768981, 10276536243, 822955247485, 58200440129470, 3799361321633144, 235172542192199514, 14040457016024386686, 817688213483194898191, 46806533018464413823463, 2647280824791216788157413, 148469293685889945755890443, 8277727866556696292321356900

LINKS

Andrew Howroyd, <a href="/A152497/b152497.txt">Table of n, a(n) for n = 1..200</a>

FORMULA

a(n) = A334774(n,5)/3. - Andrew Howroyd, May 12 2020

PROG

(PARI) \\ PeaksBySig defined in A334774.

a(n)={PeaksBySig(vector(n, i, 2), [4])[1]/3} \\ Andrew Howroyd, May 12 2020

CROSSREFS

Cf. A334774.

EXTENSIONS

Terms a(11) and beyond from Andrew Howroyd, May 12 2020

STATUS

approved

editing

#3 by Russ Cox at Sat Mar 31 12:35:19 EDT 2012

AUTHOR

_R. H. Hardin (rhhardin(AT)att.net), _, Dec 06 2008

Discussion

Sat Mar 31

12:35

OEIS Server: https://oeis.org/edit/global/875

#2 by N. J. A. Sloane at Sat Oct 02 03:00:00 EDT 2010

KEYWORD

nonn,new

nonn

AUTHOR

Ron R. H. Hardin (rhhardin(AT)att.net), Dec 06 2008

#1 by N. J. A. Sloane at Fri Jan 09 03:00:00 EST 2009

NAME

1/3 of the number of permutations of 2 indistinguishable copies of 1..n with exactly 5 local maxima.

DATA

0, 0, 0, 0, 2464, 744881, 104768981, 10276536243, 822955247485, 58200440129470

OFFSET

1,5

KEYWORD

nonn

AUTHOR

Ron Hardin (rhhardin(AT)att.net), Dec 06 2008

STATUS

approved