A059513 Variation of Boustrophedon transform applied to 1,1,1,1,... Fill an array by diagonals, in alternating directions. The first entry is 1 each time. For the next element of a diagonal, add to the previous element the elements of the row and the column the new element is in. The final element of each diagonal gives a(n).

1, 2, 6, 23, 116, 736, 5659, 50796, 521040, 6006587, 76874524, 1081439062, 16586149365, 275442822510, 4924040788654

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Example

The array begins
1 ....2 ...1 ..23 ..1 ...
1 ....4 ..19 ..48 ...
6 ...13 ..87 ...
1 ..107 ...
116 ...
1 ...

Crossrefs

Cf. A000667, A035002, A059216, A059219, A059575, A059574.

Sequence in context: A349087 A370508 A370670 * A132647 A177253 A358609

Adjacent sequences: A059510 A059511 A059512 * A059514 A059515 A059516

Keyword

easy,nonn

Author

Floor van Lamoen, Jan 23 2001

Status

approved