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A141728 Triangle read by rows T(n,k). Triangle elements are 0 and 1. Starting with 1 in the top add below a second row of (2n-1) elements (with n=2 -> 3). Moving from left to right add 1 if the number of adjacent 1's is even or add 0 if it is odd. See example below. +0
10
1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1 (list; graph; listen)
OFFSET

0,1

COMMENT

Any diagonal, read top down from right to left, expresses a periodic sequence of 0'0's and 1's Lengths of the periods are alway powers of 2. Here below the periods for the first 20 diagonals:

10

0

0110

0110

1000

0

01011010

00011110

11011000

11110000

11001010

01100000

01000110

0110

1011011101001000

0111111110000000

0000111101011010

1110000100011110

0100000111011000

1001011100001110

LINKS

Paolo P. Lava, Picture of Triangle A141728 [From Paolo P. Lava (ppl(AT)spl.at), Nov 28 2008]

EXAMPLE

.....................................1 First Row

..................................0 ... Add 0 to have an odd number of adjacent 1's

.....................................1 First Row

...................................0.0 ... Add again 0 to have an odd number of adjacent 1's

......................................1 First Row

...................................0.0.0 ... Again add 0 to have an odd number of adjacent 1's

The second row is now complete.

.....................................1 First Row

...................................0.0.0 Second Row

.................................1 ... Add 1 because there are no adjacent 1's

.....................................1 First Row

...................................0.0.0 Second Row

.................................1.0 ... Add 0 because there is one adjacent 1 (third row)

.....................................1 First Row

...................................0.0.0 Second Row

.................................1.0.1 ... Add 1 because there is no adjacent 1

.....................................1 First Row

...................................0.0.0 Second Row

.................................1.0.1.0 ... Add 0 because there is only an 1 adjacent (third row)

.....................................1 First Row

...................................0.0.0 Second Row

.................................1.0.1.0.1 ... Add 1 because there is no adjacent 1

The third row is now complete. Then repeat the process for the other rows.

CROSSREFS

Cf. A141727, A141729 - A141746.

Sequence in context: A089024 A068430 A141738 this_sequence A141737 A089011 A095111

Adjacent sequences: A141725 A141726 A141727 this_sequence A141729 A141730 A141731

KEYWORD

easy,nonn

AUTHOR

Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Jul 02 2008

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Last modified December 11 12:57 EST 2009. Contains 170656 sequences.


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