OFFSET
1,3
COMMENTS
Each positive integer n occurs n times, so the n-th row has length n.
LINKS
Reinhard Zumkeller, Rows n = 1..150 of triangle, flattened
John Brillhart, Patrick Morton, Über Summen von Rudin-Shapiroschen Koeffizienten, (German) Illinois J. Math. 22 (1978), no. 1, 126--148. MR0476686 (57 #16245). - N. J. A. Sloane, Jun 06 2012
Eric Weisstein's World of Mathematics, Rudin-Shapiro Sequence
EXAMPLE
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; ...
From Seiichi Manyama, Apr 23 2017: (Start)
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)
MATHEMATICA
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 *)
PROG
(Haskell)
a093573 n k = a093573_row n !! (k-1)
a093573_row n = take n $ elemIndices n a020986_list
a093573_tabl = map a093573_row [1..]
-- Reinhard Zumkeller, Jun 06 2012
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Eric W. Weisstein, Apr 01 2004
EXTENSIONS
Offset corrected by Reinhard Zumkeller, Jun 06 2012
STATUS
approved