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 A197818 Walsh matrix antidiagonals converted to decimal. 2
 1, 3, 5, 15, 17, 51, 93, 255, 257, 771, 1453, 3855, 4593, 13299, 23901, 65535, 65537, 196611, 371373, 983055, 1175281, 3394803, 6103645, 16711935, 16908033, 50593539, 95245741, 252706575, 301011441, 871576563, 1566432605, 4294967295 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Infinite Walsh matrix with the negative ones replaced by zeros (negated binary Walsh matrix), the antidiagonals read as binary numbers. This sequence is similar to A001317 (Sierpinski triangle rows converted to decimal). a(n) = A001317(n) iff n=0 or n is an element of A099627. LINKS Tilman Piesk, Table of n, a(n) for n = 0..1023 Tilman Piesk, Negated binary Walsh matrix of size 256 Tilman Piesk, The antidiagonals shown in a triangular matrix Wikipedia, Walsh matrix EXAMPLE Top left corner of the negated binary Walsh matrix: 1 1 1 1 1 1 1 1 1 0 1 0 1 0 1 0 1 1 0 0 1 1 0 0 1 0 0 1 1 0 0 1 1 1 1 1 0 0 0 0 1 0 1 0 0 1 0 1 1 1 0 0 0 0 1 1 1 0 0 1 0 1 1 0 The antidiagonals in binary and decimal are:          1 =   1         11 =   3        101 =   5       1111 =  15      10001 =  17     110011 =  51    1011101 =  93   11111111 = 255 PROG (PARI) N=2^5;  /* a power of 2 */ parity(x)= {     my(s=1);     while ( (x>>s),  x=bitxor(x, x>>s); s+=s; );     return( bitand(x, 1) ); } W = matrix(N, N, i, j, if(parity(bitand(i-1, j-1)), 0, 1); ); a(n) = sum(k=0, n, 2^k * W[n-k+1, k+1] ); vector(N, n, a(n-1)) /* Joerg Arndt, Mar 27 2013 */ CROSSREFS Cf. A001317, A099627. Sequence in context: A045544 A001317 A053576 * A077406 A054432 A016043 Adjacent sequences:  A197815 A197816 A197817 * A197819 A197820 A197821 KEYWORD nonn,base AUTHOR Tilman Piesk, Oct 18 2011 STATUS approved

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Last modified December 4 09:05 EST 2016. Contains 278749 sequences.