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A197819 Table of binary Walsh functions w(A001317), columns read as binary numbers. 4
0, 1, 0, 3, 2, 1, 0, 15, 10, 5, 12, 3, 6, 9, 8, 7, 2, 13, 4, 11, 14, 1, 0, 255, 170, 85, 204, 51, 102, 153, 136, 119, 34, 221, 68, 187, 238, 17, 240, 15, 90, 165, 60, 195, 150, 105, 120, 135, 210, 45, 180, 75, 30, 225, 160, 95, 10, 245, 108, 147 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
The rows of an infinite binary Walsh matrix (compare A228539) are the binary Walsh functions w(0),w(1),w(2),w(3),...
This number triangle represents the infinite binary array w(1),w(3),w(5),w(15),... (1,3,5,15,... is A001317.)
T(n,k) is column k of the (2^n) X (2^2^n) submatrix read as a binary number.
Top left 4 X 16 submatrix of the binary array:
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0
0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0
0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0
In the sequence this is represented by row 2:
0 15 10 5 12 3 6 9 8 7 2 13 4 11 14 1
A195467 is the infinite array of Gray code permutation powers. It can be defined by this binary array, which happens to be A195467 mod 2.
Each odd column is the complement of the even column on its left.
Each row of the number triangle is a self-inverse Walsh permutation. The subsequence of even entries (on the even places) divided by 2 is a self-inverse Walsh permutation too.
LINKS
Tilman Piesk, permutation matrices of row 2 and row 3
Tilman Piesk,  Explanations (including the 8x256 submatrix) and MATLAB code showing the connection with A195467
CROSSREFS
Cf. A195467 (consecutive powers of the Gray code permutation).
Cf. A001317 (Sierpinski triangle rows read like binary numbers).
Sequence in context: A111106 A370419 A321964 * A232006 A202820 A113081
KEYWORD
nonn,tabf
AUTHOR
Tilman Piesk, Oct 18 2011, reviewed Aug 25 2013
STATUS
approved

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Last modified April 25 01:35 EDT 2024. Contains 371964 sequences. (Running on oeis4.)