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

0,1

Links

Table of n, a(n) for n=0..104.

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

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.

Example

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

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.

Sequence in context: A143541 A359583 A344120 * A214090 A072784 A092436

Adjacent sequences: A090170 A090171 A090172 * A090174 A090175 A090176

Keyword

nonn,easy,tabl

Author

N. J. A. Sloane, Jan 19 2004

Extensions

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

Status

approved