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A213057 Triangle read by rows: left edge is all 1's, right edge is 1, 2, 3, 4, ...; construct an internal entriy by concatenating the two entries above it. 1
1, 1, 2, 1, 12, 3, 1, 112, 123, 4, 1, 1112, 112123, 1234, 5, 1, 11112, 1112112123, 1121231234, 12345, 6, 1, 111112, 111121112112123, 11121121231121231234, 112123123412345, 123456, 7, 1, 1111112, 111112111121112112123, 11112111211212311121121231121231234, 11121121231121231234112123123412345, 112123123412345123456, 1234567, 8 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Closely related to A004073 - see Kubo-Vakil.

After the 9th row of course we will encounter strings like 111...110, which is unsatisfactory. Still, the initial rows look nice and the sequence serves as a pointer to the Kubo-Vakil paper.

LINKS

Table of n, a(n) for n=0..35.

T. Kubo and R. Vakil, On Conway's recursive sequence, Discr. Math. 152 (1996), 225-252.

EXAMPLE

Triangle begins

1

1 2

1 12 3

1 112 123 4

1 1112 112123 1234 5

1 11112 1112112123 1121231234 12345 6

1 111112 111121112112123 11121121231121231234 112123123412345 123456 7

...

CROSSREFS

Cf. A004073, A007318.

Sequence in context: A249163 A211099 A058734 * A103187 A107722 A167128

Adjacent sequences:  A213054 A213055 A213056 * A213058 A213059 A213060

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Jun 03 2012

STATUS

approved

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Last modified December 8 21:07 EST 2016. Contains 278957 sequences.