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A117136 Triangle read by rows: row n always begins with 1. Later terms in row n are obtained by successively subtracting or adding the numbers n, n+1, n+2, until reaching 1 again. The rule is that you subtract if the result is positive, otherwise you add. 2
1, 1, 1, 2, 4, 1, 1, 3, 6, 2, 7, 1, 1, 4, 8, 3, 9, 2, 10, 1, 1, 5, 10, 4, 11, 3, 12, 2, 13, 1, 1, 6, 12, 5, 13, 4, 14, 3, 15, 2, 16, 1, 1, 7, 14, 6, 15, 5, 16, 4, 17, 3, 18, 2, 19, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Row n has length 2n+2.

LINKS

Table of n, a(n) for n=0..55.

FORMULA

T(n,0) = 1. For 0<k<=n+1, T(n,2k-1) = n+2-k, T(n,2k) = 2n+1+k. - Franklin T. Adams-Watters, Apr 26 2006

EXAMPLE

Triangle begins:

Row 0: 1 1

Row 1: 1 2 4 1

Row 2: 1 3 6 2 7 1

Row 3: 1 4 8 3 9 2 10 1

Row 4: 1 5 10 4 11 3 12 2 13 1

...

CROSSREFS

Sequence in context: A295224 A074749 A194524 * A139227 A269750 A292495

Adjacent sequences:  A117133 A117134 A117135 * A117137 A117138 A117139

KEYWORD

nonn,tabf

AUTHOR

N. J. A. Sloane, Apr 21 2006

STATUS

approved

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Last modified May 18 01:26 EDT 2021. Contains 343992 sequences. (Running on oeis4.)