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A268229
Rotate the Sierpinski triangle A047999 counterclockwise by 45 degrees to get a square array; a(n) = period of row n.
2
1, 10, 1100, 1000, 11110000, 10100000, 11000000, 10000000, 1111111100000000, 1010101000000000, 1100110000000000, 1000100000000000, 1111000000000000, 1010000000000000, 1100000000000000, 1000000000000000, 11111111111111110000000000000000
OFFSET
0,2
LINKS
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
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