

A134819


Irregular triangle read by rows: the number of hydrocarbon structures that can be drawn with a given number of carbons and units of unsaturation.


2



1, 1, 1, 1, 1, 2, 3, 2, 1, 2, 5, 9, 11, 7, 3, 3, 10, 26, 40, 40, 21, 6, 5, 25, 77, 159, 217, 185, 85, 19, 9, 56, 222, 575, 1031, 1230, 920, 356, 50, 18, 139, 654, 2082, 4679, 7437, 7982, 5308, 1804, 204, 35, 338, 1902, 7244, 19983, 40139, 57771, 56437, 33860, 10064, 832
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OFFSET

1,6


COMMENTS

Computed over a period of several years and confirmed using the Molgen program.


LINKS

David Consiglio, Jr., Table of n, a(n) for n = 1..130
Molgen, Molecular Structure Generation


EXAMPLE

Triangle begins:
1
1 1 1
1 2 3 2 1
2 5 9 11 7 3
etc.
a(3,1) = 2 because there are two structures that contain 3 carbons and have 1 unit of unsaturation (propene and cyclopropane).


CROSSREFS

Row sums give A134818.
Sequence in context: A198242 A049063 A120894 * A135267 A242406 A270469
Adjacent sequences: A134816 A134817 A134818 * A134820 A134821 A134822


KEYWORD

nice,nonn,tabf


AUTHOR

David Consiglio, Jr., Jan 28 2008, Apr 23 2008


STATUS

approved



