A093573 revision #36
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A093573
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Triangle read by rows: row n gives positions where n occurs in the Golay-Rudin-Shapiro related sequence A020986.
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1
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0, 1, 3, 2, 4, 6, 5, 7, 13, 15, 8, 12, 14, 16, 26, 9, 11, 17, 19, 25, 27, 10, 18, 20, 22, 24, 28, 30, 21, 23, 29, 31, 53, 55, 61, 63, 32, 50, 52, 54, 56, 60, 62, 64, 106, 33, 35, 49, 51, 57, 59, 65, 67, 105, 107, 34, 36, 38, 48, 58, 66, 68, 70, 104, 108, 110, 37, 39, 45
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,3
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COMMENTS
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Each positive integer n occurs n times, so the n-th row has length n.
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LINKS
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EXAMPLE
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A020986(n) for n = 0, 1, ... is 1, 2, 3, 2, 3, 4, 3, 4, 5, 6, ..., so the positions of 1, 2, 3, 4, ... are 0; 1, 3; 2, 4, 6; 5, 7, 13, 15; ...
Triangle begins:
0,
1, 3,
2, 4, 6,
5, 7, 13, 15,
8, 12, 14, 16, 26,
9, 11, 17, 19, 25, 27,
10, 18, 20, 22, 24, 28, 30,
21, 23, 29, 31, 53, 55, 61, 63,
32, 50, 52, 54, 56, 60, 62, 64, 106,
33, 35, 49, 51, 57, 59, 65, 67, 105, 107,
34, 36, 38, 48, 58, 66, 68, 70, 104, 108, 110,
... (End)
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MATHEMATICA
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With[{n = 16}, TakeWhile[#, Length@ #2 == #1 & @@ # &][[All, -1]] &@ Transpose@ {Keys@ #, Lookup[#, Keys@ #]} &[PositionIndex@ Accumulate@ Array[1 - 2 Mod[Length[FixedPointList[BitAnd[#, # - 1] &, BitAnd[#, Quotient[#, 2]]]], 2] &, n^2, 0] - 1]] // Flatten (* Michael De Vlieger, Jan 25 2020 *)
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PROG
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(Haskell)
a093573 n k = a093573_row n !! (k-1)
a093573_row n = take n $ elemIndices n a020986_list
a093573_tabl = map a093573_row [1..]
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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proposed
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