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A058257 Triangle read by rows: this is a variant of A008280 in which 2 rows go from left to right, 2 from right to left, 2 from left to right, etc. 5
1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 3, 2, 1, 0, 0, 0, 3, 5, 6, 6, 6, 0, 0, 3, 8, 14, 20, 26, 71, 71, 71, 68, 60, 46, 26, 0, 413, 342, 271, 200, 132, 72, 26, 0, 0, 0, 413, 755, 1026, 1226, 1358, 1430, 1456, 1456, 1456, 0, 0, 413, 1168, 2194, 3420, 4778, 6208, 7664, 9120, 10576 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,11

COMMENTS

Suggested by first Atkinson reference.

REFERENCES

M. D. Atkinson: Zigzag permutations and comparisons of adjacent elements, Information Processing Letters 21 (1985), 187-189.

M. D. Atkinson: Partial orders and comparison problems, Sixteenth Southeastern Conference on Combinatorics, Graph Theory and Computing, (Boca Raton, Feb 1985), Congressus Numerantium 47, 77-88.

LINKS

Reinhard Zumkeller, Rows n = 0..120 of triangle, flattened

J. Millar, N. J. A. Sloane and N. E. Young, A new operation on sequences: the Boustrophedon on transform, J. Combin. Theory, 17A 44-54 1996 (Abstract, pdf, ps).

Index entries for sequences related to boustrophedon transform

EXAMPLE

1; 0,1; 0,0,1; 1,1,1,0; 3,2,1,0,0; 0,3,5,6,6,6; ...

1

PROG

(Haskell)

a058257 n k = a058257_tabl !! n !! k

a058257_row n = a058257_tabl !! n

a058257_tabl = [1] : ox 0 [1] where

   ox turn xs = ys : ox (mod (turn + 1) 4) ys

      where ys | turn <= 1 = scanl (+) 0 xs

               | otherwise = reverse $ scanl (+) 0 $ reverse xs

-- Reinhard Zumkeller, Nov 01 2013

CROSSREFS

Cf. A058258, A008280, A000111.

Sequence in context: A085075 A321518 A267883 * A083199 A274537 A305234

Adjacent sequences:  A058254 A058255 A058256 * A058258 A058259 A058260

KEYWORD

nonn,easy,tabl,nice

AUTHOR

N. J. A. Sloane, Dec 06 2000

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Dec 12 2000

STATUS

approved

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Last modified February 21 16:08 EST 2019. Contains 320375 sequences. (Running on oeis4.)