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.

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

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 A373355

Adjacent sequences: A134816 A134817 A134818 * A134820 A134821 A134822

Keyword

nice,nonn,tabf

Author

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

Status

approved