A058257 - OEIS

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.

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 Atkinson article in Information Processing Letters.

REFERENCES

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

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

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

Index entries for sequences related to boustrophedon transform

EXAMPLE

Triangle begins:

0, 1;

0, 0, 1;

1, 1, 1, 0;

3, 2, 1, 0, 0;

0, 3, 5, 6, 6, 6;

...

PROG

(Haskell)

a058257 n k = a058257_tabl !! n !! k