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

Author

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

Keywords

• nice
• nonn
• tabf

Comments

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

Examples

			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).
		

Links

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

Crossrefs

Row sums give A134818.