A268229 Rotate the Sierpinski triangle A047999 counterclockwise by 45 degrees to get a square array; a(n) = period of row n.

1, 10, 1100, 1000, 11110000, 10100000, 11000000, 10000000, 1111111100000000, 1010101000000000, 1100110000000000, 1000100000000000, 1111000000000000, 1010000000000000, 1100000000000000, 1000000000000000, 11111111111111110000000000000000

Offset

0,2

Links

Lars Blomberg, Table of n, a(n) for n = 0..255

Example

The initial rows of the square array are:
11111111111111111111111111111111...
10101010101010101010101010101010...
11001100110011001100110011001100...
10001000100010001000100010001000...
11110000111100001111000011110000...
10100000101000001010000010100000...
11000000110000001100000011000000...
10000000100000001000000010000000...
11111111000000001111111100000000...
10101010000000001010101000000000...
11001100000000001100110000000000...
10001000000000001000100000000000...
11110000000000001111000000000000...
10100000000000001010000000000000...
11000000000000001100000000000000...
10000000000000001000000000000000...
11111111111111110000000000000000...
10101010101010100000000000000000...
...
Row 5 is
10100000101000001010000010100000...
which is periodic with period-length 8 and period 10100000, so a(5) = 10100000.

Crossrefs

Cf. A047999 (Sierpinski triangle), A268230.

Sequence in context: A339714 A069886 A133383 * A307723 A071672 A290155

Adjacent sequences: A268226 A268227 A268228 * A268230 A268231 A268232

Keyword

nonn

Author

N. J. A. Sloane, Feb 03 2016

Extensions

Corrected the example and terms a(10) and beyond - Lars Blomberg, Apr 14 2018

Status

approved