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A171176 Triangle read by rows in which row n lists 3n-1 together with the first 2n-1 positive integers, in reverse order. 9
2, 1, 5, 3, 2, 1, 8, 5, 4, 3, 2, 1, 11, 7, 6, 5, 4, 3, 2, 1, 14, 9, 8, 7, 6, 5, 4, 3, 2, 1, 17, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 20, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 23, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 26, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is also the length of the n-th L-toothpick added to the structure of A171166.

LINKS

Table of n, a(n) for n=1..90.

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Index entries for sequences related to toothpick sequences

EXAMPLE

Triangle begins:

2, 1;

5, 3, 2, 1;

8, 5, 4, 3, 2, 1;

11,7, 6, 5, 4, 3, 2, 1;

14,9, 8, 7, 6, 5, 4, 3, 2, 1;

17,11,10,9, 8, 7, 6, 5, 4, 3, 2, 1;

20,13,12,11,10,9, 8, 7, 6, 5, 4, 3, 2, 1;

23,15,14,13,12,11,10,9, 8, 7, 6, 5, 4, 3, 2, 1;

26,17,16,15,14,13,12,11,10,9, 8, 7, 6, 5, 4, 3, 2, 1;

CROSSREFS

Cf. A000027, A016789, A172310, A171164, A161165, A161166, A171172, A171173, A171174, A171175, A171177, A171178.

Cf. A132209 (row sums). [From R. J. Mathar, Mar 01 2010]

Sequence in context: A143409 A197387 A171177 * A213849 A067418 A287548

Adjacent sequences:  A171173 A171174 A171175 * A171177 A171178 A171179

KEYWORD

easy,nonn,tabf

AUTHOR

Omar E. Pol, Feb 23 2010

STATUS

approved

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Last modified November 20 05:07 EST 2019. Contains 329323 sequences. (Running on oeis4.)