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A117267 Difference row triangle of A117189. 2
1, 1, 2, 2, 3, 5, 4, 6, 9, 14, 7, 11, 17, 26, 40, 13, 20, 31, 48, 74, 114, 24, 37, 57, 88, 136, 210, 324, 44, 68, 105, 162, 250, 386, 596, 920, 81, 125, 193, 298, 460, 710, 1096, 1692, 2612 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Leftmost column of the triangle = the tribonacci sequence A000073: (1, 1, 2, 4, 7, 13...); rightmost diagonal of the triangle = A117189, binomial transform of the tribonacci sequence: (1, 2, 5, 14, 40, 114...). Difference rows of A117267 generate the triangle A117268.

LINKS

Table of n, a(n) for n=1..45.

FORMULA

Take difference rows of A117189 (binomial transform of the tribonacci sequence, A000073); and reorient to a flush left format.

EXAMPLE

Taking difference rows of A117189, we get:

1, 2, 5, 14, 40, 114,...

1, 3, 9, 26, 74,...

2, 6, 17, 48,...

4, 11, 3l,...

7, 20,...

23,...

Reorient into the triangle:

1,

1, 2,

2, 3, 5,

4, 6, 9, 14,

7, 11, 17, 26, 40,

...

CROSSREFS

Cf. A000073, A117268, A117189.

Sequence in context: A328666 A036716 A026399 * A086363 A174094 A284114

Adjacent sequences:  A117264 A117265 A117266 * A117268 A117269 A117270

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Mar 05 2006

STATUS

approved

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Last modified February 18 15:04 EST 2020. Contains 332019 sequences. (Running on oeis4.)