A090173 Triangle read by rows, related to Pascal's triangle read mod 2, starting with 0, 0, 1.

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, 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, 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

Offset: 0

Author

N. J. A. Sloane, Jan 19 2004

Keywords

• nonn
• easy
• tabl

Examples

			Triangle begins
  0;
  0,1;
  0,1,1;
  0,0,1,0;
  0,1,1,1,1;
  ...
		

Links

• Y. Moshe, The density of 0's in recurrence double sequences, J. Number Theory, 103 (2003), 109-121; see Fig. 2.

Crossrefs

Cf. A007318, A083093.

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

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

Formula

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.

Extensions

Edited and extended by Christian G. Bower, Jan 20 2004