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A026774 a(n) = T(2n-1,n-2), T given by A026769.

%I A026774 #7 Nov 01 2019 22:23:02
%S A026774 1,8,49,276,1504,8082,43193,230536,1231484,6591350,35369380,190329098,
%T A026774 1027180798,5559635866,30176648513,164237973028,896188159820,
%U A026774 4902187071922,26877397858264,147684225578318,813159429830590
%N A026774 a(n) = T(2n-1,n-2), T given by A026769.
%H A026774 G. C. Greubel, <a href="/A026774/b026774.txt">Table of n, a(n) for n = 2..500</a>
%p A026774 T:= proc(n,k) option remember;
%p A026774    if n<0 then 0;
%p A026774    elif k=0 or k=n then 1;
%p A026774    elif n=2 and k=1 then 2;
%p A026774    elif k <= (n-1)/2 then
%p A026774         procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
%p A026774    else
%p A026774        procname(n-1,k-1)+procname(n-1,k) ;
%p A026774    end if ;
%p A026774 end proc;
%p A026774 seq(T(2*n-1, n-2), n=2..30); # _G. C. Greubel_, Nov 01 2019
%t A026774 T[n_, k_]:= T[n, k]= If[n<0, 0, If[k==0 || k==n, 1, If[n==2 && k==1, 2, If[k<=(n-1)/2, T[n-1, k-1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]]]; Table[T[2*n-1, n-2], {n,2,30}] (* _G. C. Greubel_, Nov 01 2019 *)
%o A026774 (Sage)
%o A026774 @CachedFunction
%o A026774 def T(n, k):
%o A026774     if (k==0 or k==n): return 1
%o A026774     elif (n==2 and k==1): return 2
%o A026774     elif (k<=(n-1)/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
%o A026774     else: return T(n-1,k-1) + T(n-1,k)
%o A026774 [T(2*n-1, n-2) for n in (2..30)] # _G. C. Greubel_, Nov 01 2019
%Y A026774 Cf. A026769, A026770, A026771, A026772, A026773, A026775, A026776, A026777, A026778, A026779.
%K A026774 nonn
%O A026774 2,2
%A A026774 _Clark Kimberling_