cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A323222 A(n, k) = [x^k] (1 - 4*x)^(-n/2)*x/(1 - x), square array read by ascending antidiagonals with n >= 0 and k >= 0.

This page as a plain text file.
%I A323222 #21 Jan 29 2019 04:35:35
%S A323222 0,0,1,0,1,1,0,1,3,1,0,1,5,9,1,0,1,7,21,29,1,0,1,9,37,85,99,1,0,1,11,
%T A323222 57,177,341,351,1,0,1,13,81,313,807,1365,1275,1,0,1,15,109,501,1593,
%U A323222 3579,5461,4707,1,0,1,17,141,749,2811,7737,15591,21845,17577,1
%N A323222 A(n, k) = [x^k] (1 - 4*x)^(-n/2)*x/(1 - x), square array read by ascending antidiagonals with n >= 0 and k >= 0.
%C A323222 General asymptotic formula for g.f. (1 - 4*x)^(-j/2)*x/(1 - x) and fixed j>0 is a(n) ~ n^(j/2 - 1) * 4^n / (3*Gamma(j/2)). - _Vaclav Kotesovec_, Jan 29 2019
%F A323222 For n>0 and k>0 let X(n, k) denote the set of all tuples of length n with elements from {0, ..., k-1} with sum < k. Let b(m) = binomial(2*m, m). Then A(n, k) = Sum_{(j1,...,jn) in X(n, k)} b(j1)*b(j2)*...*b(jn).
%e A323222 [n\k] 0  1   2    3     4      5       6       7        8         9
%e A323222 -------------------------------------------------------------------
%e A323222 [0]   0, 1,  1,   1,    1,     1,      1,      1,       1,        1, ... A057427
%e A323222 [1]   0, 1,  3,   9,   29,    99,    351,   1275,    4707,    17577, ... A006134
%e A323222 [2]   0, 1,  5,  21,   85,   341,   1365,   5461,   21845,    87381, ... A002450
%e A323222 [3]   0, 1,  7,  37,  177,   807,   3579,  15591,   67071,   285861, ... A277178
%e A323222 [4]   0, 1,  9,  57,  313,  1593,   7737,  36409,  167481,   757305, ... A014916
%e A323222 [5]   0, 1, 11,  81,  501,  2811,  14823,  74883,  366603,  1752273, ... A323223
%e A323222 [6]   0, 1, 13, 109,  749,  4589,  26093, 140781,  730605,  3679725, ...
%e A323222 [7]   0, 1, 15, 141, 1065,  7071,  43107, 247311, 1355847,  7175661, ...
%e A323222 [8]   0, 1, 17, 177, 1457, 10417,  67761, 411825, 2377905, 13191345, ...
%e A323222 [9]   0, 1, 19, 217, 1933, 14803, 102319, 656587, 3982195, 23104441, ...
%e A323222 Triangle given by antidiagonals:
%e A323222 0;
%e A323222 0, 1;
%e A323222 0, 1,  1;
%e A323222 0, 1,  3,   1;
%e A323222 0, 1,  5,   9,   1;
%e A323222 0, 1,  7,  21,  29,    1;
%e A323222 0, 1,  9,  37,  85,   99,    1;
%e A323222 0, 1, 11,  57, 177,  341,  351,    1;
%e A323222 0, 1, 13,  81, 313,  807, 1365, 1275,    1;
%e A323222 0, 1, 15, 109, 501, 1593, 3579, 5461, 4707, 1;
%p A323222 Row := proc(n, len) local ogf, ser; ogf := (1 - 4*x)^(-n/2)*x/(1 - x);
%p A323222 ser := series(ogf, x, (n+1)*len+1); seq(coeff(ser, x, j), j=0..len) end:
%p A323222 for n from 0 to 9 do Row(n, 9) od;
%t A323222 BF[N_, K_] := Module[{}, r[n_, k_] := FrobeniusSolve[ConstantArray[1, n], k];
%t A323222 X[n_] := Flatten[Table[r[N, j], {j, 0, n - 1}], 1];
%t A323222 CentralBinomial[n_] := Binomial[2 n, n];
%t A323222 Sum[Product[CentralBinomial[m[[i]]], {i, 1, N}], {m , X[K]}]];
%t A323222 Trow[n_] := Table[BF[n, k], {k, 0, 9}]; Table[Trow[n], {n, 1, 9}]
%Y A323222 Sums of antidiagonals are A323217. Main diagonal is A323219.
%Y A323222 Rows: A057427 (n=0), A006134 (n=1), A002450 (n=2), A277178 (n=3), A014916 (n=4), A323223 (n=5).
%Y A323222 Columns: A005408 (k=2), A059993 (k=3), A323218 (k=4).
%Y A323222 Similar array based on Catalan numbers is A323224.
%K A323222 nonn,tabl
%O A323222 0,9
%A A323222 _Peter Luschny_, Jan 24 2019