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A141743
Triangle read by rows T(n,k). Triangle elements are 0 and 1. Starting with 0 in the top add below a second row of (2n-1) elements (with n=2 -> 3). Moving from left to right add 0 if the number of adjacent 1's is odd or add 1 if it is even or null. See example below.
5
0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1
OFFSET
0,1
COMMENTS
Any diagonal, read top down from right to left, expresses a periodic sequence of 0's and 1's. Lengths of the periods are always powers of 2. Here below the periods for the first 20 diagonals:
01
0
1100
1100
1110
0
00011110
10010110
00101000
00011110
10000100
01001000
00011010
1110
0101011110101000
1011000101001110
0111111011010100
1000100101110110
0111011101000100
1011010110000110
EXAMPLE
...............................0 First Row
............................1.... Add 1 to have an odd number of adjacent 1's
..............................0 First Row
............................1.0.. Add 0 because there is an odd number of adjacent 1's (second row)
..............................0 First Row
............................1.0.1 Again add 1 because there is a null number of adjacent 1's.
The second row is now complete.
..............................0 First Row
............................1.0.1 Second Row
..........................0... Add 0 because there is only an 1 adjacent (second row)
..............................1 First Row
............................1.0.1 Second Row
..........................0.0.... Add 0 because there is only an 1 adjacent (second row)
.............................0 First Row
...........................1.0.1 Second Row
.........................0.0.1 Add 1 because there are two 1's adjacent (second row)
.............................0 First Row
...........................1.0.1 Second Row
.........................0.0.1.1 Add 1 because there are two 1's adjacent (second and third row)
.............................0 First Row
...........................1.0.1 Second Row
.........................0.0.1.1.1 Add 1 because there are two 1's adjacent (second and third row)
The third row is now complete. Then repeat the process for the other rows.
CROSSREFS
Sequence in context: A213676 A309752 A209355 * A268384 A358670 A288524
KEYWORD
easy,nonn,tabf
AUTHOR
STATUS
approved