A059235 - OEIS

A059235

The array in A059219 read by antidiagonals in the direction in which it was constructed.

1, 0, 1, 0, 1, 2, 0, 2, 3, 5, 0, 5, 8, 12, 15, 0, 15, 27, 39, 48, 55, 0, 55, 103, 152, 190, 221, 239, 0, 239, 460, 680, 871, 1025, 1137, 1199, 0, 1199, 2336, 3471, 4493, 5374, 6062, 6553, 6810, 0, 6810, 13363, 19903, 25958, 31351, 35884, 39399, 41847, 43108, 0

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,6

LINKS

G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened

Index entries for sequences related to boustrophedon transform

EXAMPLE

The array begins

1 1 0 5 0 55 0 ...

0 1 3 5 48 55 ...

2 2 8 39 103 ...

0 12 27 152 ...

15 15 190 ...

0 221 ...

MATHEMATICA

max = 10; t[0, 0] = 1; t[0, _?EvenQ] = 0; t[_?OddQ, 0] = 0; t[n_, k_] /; OddQ[n+k](*up*):= t[n, k] = t[n+1, k-1] + Sum[t[n, j], {j, 0, k-1}]; t[n_, k_] /; EvenQ[n+k](*down*):= t[n, k] = t[n-1, k+1] + Sum[t[j, k], {j, 0, n-1}]; Table[tn = Table[t[n-k, k], {k, 0, n}]; If[OddQ[n], tn, tn // Reverse] , {n, 0, max}] // Flatten (* Jean-François Alcover, Nov 20 2012 *)

CROSSREFS

Cf. A000667, A059216, A059219, A059217, A059220.

Sequence in context: A257092 A374705 A028376 * A261216 A308107 A323167

Adjacent sequences: A059232 A059233 A059234 * A059236 A059237 A059238

KEYWORD

easy,nonn,tabl,nice

AUTHOR

N. J. A. Sloane, Jan 18 2001

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Jan 24 2001

STATUS

approved