The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A297195 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A297195

Number of bitriangular permutations (row sums of A272644 if that triangle is prefixed with a row for n=1).
(history; published version)

#12 by Alois P. Heinz at Fri Apr 03 16:45:13 EDT 2020

STATUS

proposed

approved

#11 by Jean-François Alcover at Fri Apr 03 13:21:42 EDT 2020

STATUS

editing

proposed

#10 by Jean-François Alcover at Fri Apr 03 13:21:30 EDT 2020

MATHEMATICA

A272644[n_, m_] := Sum[StirlingS2[m+1, i+1] (-1)^(m-i) i^(n-m) i!, {i, 0, m}];

a[n_] := If[n == 1, 1, Sum[A272644[n, m], {m, 1, n-1}]];

Array[a, 24] (* Jean-François Alcover, Apr 03 2020 *)

STATUS

approved

editing

#9 by Alois P. Heinz at Sun Jan 27 17:58:40 EST 2019

STATUS

reviewed

approved

#8 by Michel Marcus at Sun Jan 27 17:28:23 EST 2019

STATUS

proposed

reviewed

#7 by Jon E. Schoenfield at Sun Jan 27 17:07:50 EST 2019

STATUS

editing

proposed

#6 by Jon E. Schoenfield at Sun Jan 27 17:07:47 EST 2019

MAPLE

seq(A297195(n), n=1..30) ; 3 _# _R. J. Mathar_, Mar 04 2018

STATUS

approved

editing

#5 by R. J. Mathar at Sun Mar 04 14:47:49 EST 2018

STATUS

editing

approved

#4 by R. J. Mathar at Sun Mar 04 14:47:34 EST 2018

DATA

1, 1, 2, 7, 28, 133, 726, 4483, 30896, 235105, 1957930, 17712799, 172980804, 1813760317, 20323234814, 242353047355, 3064550705752, 40958281206169, 576917769130578, 8541793624670551, 132623408805525740, 2154730841214003061, 36560670776303600422, 646697046042017004787

MAPLE

A297195 := proc(n)

if n = 1 then

1;

else

add(A272644(n, m), m=1..n-1) ;

end if;

end proc:

seq(A297195(n), n=1..30) ; 3 R. J. Mathar, Mar 04 2018

KEYWORD

nonn,easy,more

STATUS

approved

editing

#3 by N. J. A. Sloane at Wed Jan 10 21:56:34 EST 2018

STATUS

editing

approved