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%I #30 Dec 08 2024 02:27:36
%S 0,15,7,8,3,12,4,11,1,14,6,9,2,13,5,10
%N The sequency numbers of the 16 rows of a Hadamard-Walsh matrix of order 16.
%C See A240908 for context. This sequence is the natural sequency ordering for an order 16 matrix.
%H N. J. A. Sloane, <a href="http://neilsloane.com/hadamard">A Library of Hadamard Matrices</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HadamardMatrix.html">Hadamard Matrix</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Walsh_matrix">Walsh matrix</a>
%F Recursion: H(2)=[1 1; 1 -1]; H(n) = H(n-1)*H(2), where * is Kronecker matrix product.
%F a(n) = A131271(4,n) - 1. - _Mathew Englander_, Jun 19 2021
%e This is a fixed length sequence of only 16 values, as given.
%Y Cf. A240908 "natural order" sequencies for Hadamard-Walsh matrix, order 8.
%Y Cf. A240910 "natural order" sequencies for Hadamard-Walsh matrix, order 32.
%Y Cf. A153141 "dyadic order" sequencies for Hadamard-Walsh matrix, all orders.
%Y Cf. A000975(n) is sequency of last row of H(n). - _William P. Orrick_, Jun 28 2015
%Y Cf. A131271 (row 4, minus 1).
%K nonn,fini,full
%O 1,2
%A _Ross Drewe_, Apr 14 2014
%E Definition of H(n) corrected by _William P. Orrick_, Jun 28 2015