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A055827 a(n) = T(2n+3,n), array T as in A055818.

%I A055827 #11 Jan 23 2020 12:27:07
%S A055827 1,23,144,848,4880,27816,157920,895264,5074272,28772280,163262704,
%T A055827 927203184,5270629104,29988361032,170780080320,973422085184,
%U A055827 5552990609344,31702646247768,181128948471888,1035584204252560
%N A055827 a(n) = T(2n+3,n), array T as in A055818.
%H A055827 G. C. Greubel, <a href="/A055827/b055827.txt">Table of n, a(n) for n = 0..250</a>
%p A055827 T:= proc(i, j) option remember;
%p A055827       if i=0 or j=0 then 1
%p A055827     else add(add(T(h,m), m=0..j), h=0..i-1)
%p A055827   fi; end:
%p A055827 seq(T(n+3, n), n=0..30); # _G. C. Greubel_, Jan 22 2020
%t A055827 T[i_, j_]:= T[i, j]= If[i==0 || j==0, 1, Sum[T[h, m], {h,0,i-1}, {m,0,j}]]; Table[T[n+3, n], {n,0,25}] (* _G. C. Greubel_, Jan 22 2020 *)
%o A055827 (Sage)
%o A055827 @CachedFunction
%o A055827 def T(i, j):
%o A055827     if (i==0 or j==0): return 1
%o A055827     else: return sum(sum(T(h,m) for m in (0..j)) for h in (0..i-1))
%o A055827 [T(n+3, n) for n in (0..30)] # _G. C. Greubel_, Jan 22 2020
%Y A055827 Cf. A055818, A055819, A055820, A055821, A055822, A055823, A055824, A055825, A055826, A055828, A055829.
%K A055827 nonn
%O A055827 0,2
%A A055827 _Clark Kimberling_, May 28 2000