|
|
|
|
|
|
|
|
|
#40 by Alois P. Heinz at Tue Apr 20 12:58:35 EDT 2021
|
|
|
|
|
|
|
|
#39 by Alois P. Heinz at Tue Apr 20 12:57:52 EDT 2021
|
|
| CROSSREFS
|
Cf. Column k=0 of A047921.
|
|
| STATUS
|
approved
editing
|
|
|
|
|
|
|
#38 by Susanna Cuyler at Sat May 23 14:30:36 EDT 2020
|
|
|
|
|
|
|
|
#37 by Jean-François Alcover at Sat May 23 08:31:38 EDT 2020
|
|
|
|
|
|
|
|
#36 by Jean-François Alcover at Sat May 23 08:31:32 EDT 2020
|
|
| MATHEMATICA
|
d[0] = 1; d[n_] := d[n] = n d[n - 1] + (-1)^n;
T[n_, k_] := If[n == 0 && k == 0, 1, If[k <= n/2, Binomial[n - k, k] d[n + 1 - k]/(n - k), 0]];
a[n_] := Sum[T[n, k], {k, 0, Quotient[n, 2]}];
a /@ Range[0, 25] (* Jean-François Alcover, May 23 2020 *)
|
|
| STATUS
|
approved
editing
|
|
|
|
|
|
|
#35 by Alois P. Heinz at Sun Jul 21 17:43:12 EDT 2019
|
|
|
|
|
|
|
|
#34 by Alois P. Heinz at Sun Jul 21 17:43:07 EDT 2019
|
|
| LINKS
|
Alois P. Heinz, <a href="/A002628/b002628.txt">Table of n, a(n) for n = 0..450</a>
|
|
|
|
|
|
|
#33 by Alois P. Heinz at Sun Jul 21 17:40:47 EDT 2019
|
|
| MAPLE
|
# third Maple program:
a:= proc(n) option remember; `if`(n<5,
[1$2, 2, 5, 21][n+1], (n-3)*a(n-1)+(3*n-6)*a(n-2)+
(4*n-12)*a(n-3)+(3*n-12)*a(n-4)+(n-5)*a(n-5))
end:
seq(a(n), n=0..25); # Alois P. Heinz, Jul 21 2019
|
|
|
|
|
|
|
#32 by Alois P. Heinz at Sun Jul 21 17:35:16 EDT 2019
|
|
|
|
|
|
|
|
#31 by Alois P. Heinz at Sun Jul 21 17:25:39 EDT 2019
|
|
| MAPLE
|
d[-1]:= 0: for n from 0 to 51 do d[n] := n*d[n-1]+(-1)^n end do: a:= proc(n) add(binomial(n-k, k)*(d[n-k]+d[n-k-1]), k = 0..floor((1/2)*n)) end proc: seq(a(n), n = 0..25); # Emeric Deutsch, Sep 06 2010
|
|
|
|
|
|
