A090173 - OEIS

%I #14 Oct 27 2021 15:02:47

%S 0,0,1,0,1,1,0,0,1,0,0,1,1,1,1,0,1,1,1,1,1,0,0,0,1,1,0,0,0,1,0,0,1,0,

%T 0,1,0,1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1,1,1,1,1,0,1,

%U 1,0,1,1,1,1,1,0,1,1,0,0,0,0,0,1,1,1,1,0,0,0,0,0,1,0,0,0,1,1,1,1,1,0,0,0,1

%N Triangle read by rows, related to Pascal's triangle read mod 2, starting with 0, 0, 1.

%H Y. Moshe, <a href="http://dx.doi.org/10.1016/S0022-314X(03)00103-3">The density of 0's in recurrence double sequences</a>, J. Number Theory, 103 (2003), 109-121; see Fig. 2.

%F T(n, k) = T(n-1, k) + T(n-1, k-1) + T(n-2, k) + T(n-2, k-1) + T(n-2, k-2) for n >= 2, k >= 0, with initial conditions specified by first two rows.

%e Triangle begins

%e   0;

%e   0,1;

%e   0,1,1;

%e   0,0,1,0;

%e   0,1,1,1,1;

%e   ...

%Y Cf. A007318, A083093.

%Y Cf. A090171, A090172, A090174, A091533, A091562, A205575 (same recurrence).

%Y a(n, k) = A090174(n-1, k-1), k>0, 0 otherwise.

%K nonn,easy,tabl

%O 0,1

%A _N. J. A. Sloane_, Jan 19 2004

%E Edited and extended by _Christian G. Bower_, Jan 20 2004