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A171661 Triangle T(n,k) (n >= 0, 0 <= k <= n) read by rows: T(n,0) = T(n,1) = A000984(n); for n >= 2 and k >= 2, T(n,k) = T(n,k-1) - T(n-1,k-2).

%I A171661 #4 Nov 03 2016 07:28:52
%S A171661 1,2,2,6,6,4,20,20,14,8,70,70,50,30,16,252,252,182,112,62,32,924,924,
%T A171661 672,420,238,126,64,3432,3432,2508,1584,912,492,254,128,12870,12870,
%U A171661 9438,6006,3498,1914,1002,510,256,48620,48620,35750,22880,13442,7436
%N A171661 Triangle T(n,k) (n >= 0, 0 <= k <= n) read by rows: T(n,0) = T(n,1) = A000984(n); for n >= 2 and k >= 2, T(n,k) = T(n,k-1) - T(n-1,k-2).
%e A171661 Triangle starts:
%e A171661 1
%e A171661 2,2
%e A171661 6,6,4
%e A171661 20,20,14,8
%e A171661 70,70,50,30,16
%Y A171661 Cf. A000984, A172021.
%K A171661 nonn,tabl
%O A171661 0,2
%A A171661 _Mark Dols_, Dec 14 2009
%E A171661 Edited by _N. J. A. Sloane_, Jan 24 2010
%E A171661 More terms from _Mark Dols_, Jan 24 2010