|
|
|
|
#16 by Vaclav Kotesovec at Sat Dec 05 05:51:45 EST 2020
|
|
|
|
#15 by Vaclav Kotesovec at Sat Dec 05 05:51:21 EST 2020
|
| FORMULA
|
a(n) ~ c * 4^n, where c = Product_{k>=1} 1/(1-1/4^k) = A065446 * A132020 = 1.4523536424495970158347... . - Vaclav Kotesovec, Mar 19 2015
|
| STATUS
|
proposed
editing
|
|
|
|
#14 by Jean-François Alcover at Sat Dec 05 04:15:11 EST 2020
|
|
|
|
#13 by Jean-François Alcover at Sat Dec 05 04:14:58 EST 2020
|
| MATHEMATICA
|
b[n_, i_] := b[n, i] = If[n==0, 1, If[i<1, 0, b[n, i-1]+If[i>n, 0, 4 b[n-i, i]]]];
a[n_] := b[n, n];
a /@ Range[0, 25] (* Jean-François Alcover, Dec 05 2020, after Alois P. Heinz *)
|
| STATUS
|
approved
editing
|
|
|
|
#12 by Susanna Cuyler at Thu Apr 12 22:23:16 EDT 2018
|
|
|
|
#11 by Ilya Gutkovskiy at Thu Apr 12 16:12:27 EDT 2018
|
|
|
|
#10 by Ilya Gutkovskiy at Thu Apr 12 13:58:59 EDT 2018
|
| FORMULA
|
G.f.: Sum_{i>=0} 4^i*x^i/Product_{j=1..i} (1 - x^j). - Ilya Gutkovskiy, Apr 12 2018
|
| STATUS
|
approved
editing
|
|
|
|
#9 by Bruno Berselli at Sat Nov 21 00:45:23 EST 2015
|
|
|
|
#8 by Vladimir Reshetnikov at Fri Nov 20 20:48:02 EST 2015
|
|
|
|
#7 by Vladimir Reshetnikov at Fri Nov 20 20:48:00 EST 2015
|
| MATHEMATICA
|
(O[x]^20 - 3/QPochhammer[4, x])[[3]] (* Vladimir Reshetnikov, Nov 20 2015 *)
|
| STATUS
|
approved
editing
|
|
|
|