The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A201687 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A201687

a(1)=0; a(n) = b(n) - Sum_{r=1..n-1} a(r)*b(n-1-r), where b(n) = A000085(n).
(history; published version)

#23 by Michael De Vlieger at Fri Apr 15 10:32:44 EDT 2022

STATUS

proposed

approved

#22 by Michel Marcus at Fri Apr 15 08:27:19 EDT 2022

STATUS

editing

proposed

#21 by Michel Marcus at Fri Apr 15 08:27:15 EDT 2022

LINKS

J.-L. Baril, <a href="httphttps://www.combinatoricsdoi.org/ojs/index10.php/eljc/article/view37236/v18i1p178665">Classical sequences revisited with permutations avoiding dotted pattern</a>, Electronic Journal of Combinatorics, 18 (2011), #P178. See Table 3.

STATUS

proposed

editing

#20 by Jean-François Alcover at Fri Apr 15 07:33:10 EDT 2022

STATUS

editing

proposed

#19 by Jean-François Alcover at Fri Apr 15 07:33:06 EDT 2022

MATHEMATICA

b[n_] := b[n] = If[n < 1, 1, b[n - 1] + (n - 1)*b[n - 2]];

a[n_] := a[n] = If[n < 2, 0, b[n] - Sum[a[r]*b[n - 1 - r], {r, 1, n - 1}]];

Table[a[n], {n, 1, 28}] (* Jean-François Alcover, Apr 15 2022, after Alois P. Heinz *)

STATUS

approved

editing

#18 by Alois P. Heinz at Thu Apr 14 08:00:25 EDT 2022

STATUS

editing

approved

#17 by Alois P. Heinz at Thu Apr 14 08:00:22 EDT 2022

MAPLE

b:= proc(n) option remember; `if`(n<1, 1, b(n-1)+(n-1)*b(n-2)) end:

a:= proc(n) option remember; `if`(n<2, 0,

b(n)-add(a(r)*b(n-1-r), r=1..n-1))

end:

seq(a(n), n=1..28); # Alois P. Heinz, Apr 14 2022

STATUS

approved

editing

#16 by Alois P. Heinz at Thu Apr 14 07:56:32 EDT 2022

STATUS

editing

approved

#15 by Alois P. Heinz at Thu Apr 14 07:56:26 EDT 2022

DATA

0, 2, 2, 6, 14, 44, 134, 462, 1616, 6062, 23306, 93996, 389102, 1671158, 7360256, 33418374, 155359922, 741476492, 3617591462, 18065875422, 92087408048, 479382896030, 2543670789962, 13759520646636, 75769638724382, 424727826838886, 2420944511425472

STATUS

approved

editing

#14 by Bruno Berselli at Fri Feb 12 05:05:23 EST 2016

STATUS

reviewed

approved