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A126886 Triangle read by rows, arising in enumeration of 4-trees by diameter. 0
1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 5, 6, 8, 7, 7, 5, 5, 3, 2, 1, 1, 1, 2, 7, 12, 23, 30, 42, 47, 55, 53, 53, 45, 40, 29, 23 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,8

COMMENTS

See reference for precise definition.

LINKS

Table of n, a(n) for n=0..37.

A. T. Balaban, J. W. Kennedy and L. V. Quintas, The number of alkanes having n carbons and a longest chain of length d, J. Chem. Education, 65 (4 (1988), 304-313.

EXAMPLE

Triangle begins:

1

1

1 1 1

1 1 2 1 1

1 2 5 6 8 7 7 5 5 3 2 1 1

1 2 7 12 23 30 42 47 55 53 53 45 40 29 23 ...

CROSSREFS

Cf. A000602 (diagonal sums when rows are displaced by the appropriate amounts), A036437.

Sequence in context: A273894 A308035 A221131 * A179272 A264753 A165680

Adjacent sequences:  A126883 A126884 A126885 * A126887 A126888 A126889

KEYWORD

nonn,tabf

AUTHOR

N. J. A. Sloane, Aug 04 2007

STATUS

approved

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Last modified November 19 22:34 EST 2019. Contains 329323 sequences. (Running on oeis4.)