Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #6 Jan 05 2017 02:54:34
%S 1,1,3,11,47,219,1081,5557,29439,159611,881405,4940385,28035205,
%T 160751005,929923395,5420717819,31809479855,187757573787,
%U 1114012352029,6640357243537,39746256802185,238796968208537,1439587364576015
%N Right edge of triangle in A059283.
%H G. C. Greubel, <a href="/A059284/b059284.txt">Table of n, a(n) for n = 0..1000</a>
%F G.f.: -(-2+(-3*w^2-6*w+1)^(1/2))/(1+w)^2.
%t T[0,0] = 1; T[n_,0] = 0; T[n_, k_] /; 0 <= k <= n := T[n, k] = T[n, k - 1] + T[n - 1, k - 1] + T[n - 1, k] + T[n - 2, k - 1]; T[_, _] = 0; Table[T[n,n], {n,0,25}] (* _G. C. Greubel_, Jan 04 2016 *)
%Y Cf. A059283, A059226.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Jan 24 2001