Original entry on oeis.org
1, 3, 10, 41, 116, 427, 1240, 4181, 12472, 40091, 121364, 380701, 1160186, 3593969, 10979532, 33785469, 103258800, 316532947, 966976444, 2957131673, 9026437602, 27558146133, 84043120308, 256263107177, 780817641926
Offset: 0
-
swing := proc(n) option remember; if n = 0 then 1 elif
irem(n, 2) = 1 then swing(n-1)*n else 4*swing(n-1)/n fi end:
a := proc(n) local i,k; add(add(binomial(n-k,n-i)*swing(i),i=k..n),k=0..n) end:
-
sf[n_] := n!/Quotient[n, 2]!^2; t[n_, k_] := Sum[Binomial[n - k, n - i]*sf[i], {i, k, n}]; Table[Sum[t[n, k], {k, 0, n}], {n, 0, 50}] (* G. C. Greubel, Aug 06 2017 *)
A163842
Triangle interpolating the swinging factorial (A056040) restricted to odd indices with its binomial transform. Same as interpolating the beta numbers 1/beta(n,n) (A002457) with (A163869). Triangle read by rows, for n >= 0, k >= 0.
Original entry on oeis.org
1, 7, 6, 43, 36, 30, 249, 206, 170, 140, 1395, 1146, 940, 770, 630, 7653, 6258, 5112, 4172, 3402, 2772, 41381, 33728, 27470, 22358, 18186, 14784, 12012, 221399, 180018, 146290, 118820, 96462, 78276, 63492, 51480
Offset: 0
Triangle begins:
1;
7, 6;
43, 36, 30;
249, 206, 170, 140;
1395, 1146, 940, 770, 630;
7653, 6258, 5112, 4172, 3402, 2772;
41381, 33728, 27470, 22358, 18186, 14784, 12012;
-
# Computes n rows of the triangle. For the functions 'SumTria' and 'swing' see A163840.
a := n -> SumTria(k->swing(2*k+1),n,true);
-
sf[n_] := n!/Quotient[n, 2]!^2; t[n_, k_] := Sum[Binomial[n-k, n-i]*sf[2*i+1], {i, k, n}]; Table[t[n, k], {n, 0, 7}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jun 28 2013 *)
A163841
Triangle interpolating the swinging factorial (A056040) restricted to even indices with its binomial transform. Same as interpolating bilateral Schroeder paths (A026375) with the central binomial coefficients (A000984).
Original entry on oeis.org
1, 3, 2, 11, 8, 6, 45, 34, 26, 20, 195, 150, 116, 90, 70, 873, 678, 528, 412, 322, 252, 3989, 3116, 2438, 1910, 1498, 1176, 924, 18483, 14494, 11378, 8940, 7030, 5532, 4356, 3432, 86515, 68032, 53538
Offset: 0
Triangle begins
1;
3, 2;
11, 8, 6;
45, 34, 26, 20;
195, 150, 116, 90, 70;
873, 678, 528, 412, 322, 252;
3989, 3116, 2438, 1910, 1498, 1176, 924;
- G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened
- Peter Luschny, Die schwingende Fakultät und Orbitalsysteme, August 2011.
- Peter Luschny, Swinging Factorial.
- Tony D. Noe, On the Divisibility of Generalized Central Trinomial Coefficients, Journal of Integer Sequences, Vol. 9 (2006), Article 06.2.7.
-
Computes n rows of the triangle. For the functions 'SumTria' and 'swing' see A163840.
a := n -> SumTria(k->swing(2*k),n,true);
-
sf[n_] := n!/Quotient[n, 2]!^2; t[n_, k_] := Sum[Binomial[n - k, n - i]*sf[2*i], {i, k, n}]; Table[t[n, k], {n, 0, 8}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jun 28 2013 *)
Showing 1-3 of 3 results.
Comments