A177990 Triangle read by rows, variant of A070909, a cellular automaton.

1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1

Offset: 1

Author

Gary W. Adamson, May 16 2010

Keywords

• nonn
• tabl

Comments

A070909 * A177990 = A177991

A007318 * A177990 = A177992

A177990 * A007318 = A177993

Examples

			First few rows of the triangle =
1;
0, 1;
0, 1, 1;
0, 1, 0, 1;
0, 1, 0, 1, 1;
0, 1, 0, 1, 0, 1;
0, 1, 0, 1, 0, 1, 1;
0, 1, 0, 1, 0, 1, 0, 1;
0, 1, 0, 1, 0, 1, 0, 1, 1;
0, 1, 0, 1, 0, 1, 0, 1, 0, 1;
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1;
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1;
...
		

Crossrefs

Cf. A070909, A177991, A177992, A177993.

Programs

Mathematica

rows = 10; ca = CellularAutomaton[28, {{1}, 0}, rows]; Table[ca[[k, 2 ;; k]], {k, 2, rows+1}] // Flatten (* Jean-François Alcover, Jul 12 2017 *)

Formula

Infinite lower triangular matrix, variant of A070909: Columns alternate between (1,0,0,0,...) and (1,1,1,...); whereas A070909 leftmost column = (1,1,1,...).