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A117137 Same as triangle in A117136, but omit final 1 from each row. 1
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 (list; graph; refs; listen; history; text; internal format)
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: A277618 A219250 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

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Last modified June 14 12:04 EDT 2021. Contains 345025 sequences. (Running on oeis4.)