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A255723 Another variant of Per Nørgård's "infinity sequence", cf. A004718: t(0) = 0; t(4*n) = t(n); t(4*n+1) = t(n) - 2; t(4*n+2) = -t(n) - 1; t(4*n+3) = t(n) + 2.

%I A255723 #15 Oct 06 2017 11:36:41
%S A255723 0,-2,-1,2,-2,-4,1,0,-1,-3,0,1,2,0,-3,4,-2,-4,1,0,-4,-6,3,-2,1,-1,-2,
%T A255723 3,0,-2,-1,2,-1,-3,0,1,-3,-5,2,-1,0,-2,-1,2,1,-1,-2,3,2,0,-3,4,0,-2,
%U A255723 -1,2,-3,-5,2,-1,4,2,-5,6,-2,-4,1,0,-4,-6,3,-2,1,-1
%N A255723 Another variant of Per Nørgård's "infinity sequence", cf. A004718: t(0) = 0; t(4*n) = t(n); t(4*n+1) = t(n) - 2; t(4*n+2) = -t(n) - 1; t(4*n+3) = t(n) + 2.
%C A255723 Per Nørgård's surname is also written as Noergaard;
%C A255723 example of a sequence sharing with A004718 some main characterizing properties, see link (chapter 7).
%D A255723 Yu Hin (Gary) Au, Christopher Drexler-Lemire, and Jeffrey Shallit, "Notes and note pairs in Norgard's infinity series", J. of Mathematics and Music (2017). DOI:  http://dx.doi.org/10.1080/17459737.2017.1299807
%H A255723 Reinhard Zumkeller, <a href="/A255723/b255723.txt">Table of n, a(n) for n = 0..10000</a>
%H A255723 Christopher Drexler-Lemire, Jeffrey Shallit, <a href="http://arxiv.org/abs/1402.3091">Notes and Note-Pairs in Noergaard's Infinity Series</a>, arXiv:1402.3091 [math.CO], page 12f.
%H A255723 Jørgen Mortensen, <a href="http://www.pernoergaard.dk/eng/strukturer/uendelig/uene.html">"Is Per Nørgård's infinity series unique?"</a>
%o A255723 (Haskell)
%o A255723 a255723 n = a255723_list !! n
%o A255723 a255723_list = 0 : concat (transpose [map (subtract 2) a255723_list,
%o A255723                                       map (-1 -) a255723_list,
%o A255723                                       map (+ 2) a255723_list,
%o A255723                                       tail a255723_list])
%Y A255723 Cf. A004718, A256184, A087808, A085144.
%K A255723 sign
%O A255723 0,2
%A A255723 _Reinhard Zumkeller_, Mar 19 2015