A117137 Same as triangle in A117136, but omit final 1 from each row.

1, 1, 2, 4, 1, 3, 6, 2, 7, 1, 4, 8, 3, 9, 2, 10, 1, 5, 10, 4, 11, 3, 12, 2, 13, 1, 6, 12, 5, 13, 4, 14, 3, 15, 2, 16, 1, 7, 14, 6, 15, 5, 16, 4, 17, 3, 18, 2, 19, 1

Offset

0,3

Comments

Row n has length 2n+1.

Links

Table of n, a(n) for n=0..49.

Example

Triangle begins:
Row 0: 1
Row 1: 1 2 4
Row 2: 1 3 6 2 7
Row 3: 1 4 8 3 9 2 10
Row 4: 1 5 10 4 11 3 12 2 13
...

Crossrefs

Cf. A117136, A046901, A008344.

The segments of A046901 appear as rows 2, 7, 22, 67, ... (A060816) of this array.

Sequence in context: A376128 A361643 A282891 * A002344 A011233 A293463

Adjacent sequences: A117134 A117135 A117136 * A117138 A117139 A117140

Keyword

nonn,tabf

Author

N. J. A. Sloane, Apr 21 2006

Status

approved