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Search: id:A134818
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| A134818 |
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Number of hydrocarbon structures that can be drawn (excluding stereoisomers) for n carbon atoms. |
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+0
2
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| 1, 3, 9, 37, 146, 772, 4449, 30307, 228605, 1921464, 17652327, 171636857
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Computed over a period of several years, and confirmed using the Molgen program.
Terms for n = 8,9,10 calculated using an exhaustive algorithm and Nauty. The algorithm correctly found the 7 known terms and the known acyclic hydrocarbons (up to n=10, see A002986) were extracted from the results correctly. - Vesa Linja-aho (vesa.linja-aho(AT)tkk.fi), Apr 17 2008
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LINKS
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Brendan McKay, Nauty
Molgen, Publications
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EXAMPLE
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There are 4449 hydrocarbons with 7 carbons.
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CROSSREFS
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A134819 gives the number of possible structures, broken down by units of unsaturation
Adjacent sequences: A134815 A134816 A134817 this_sequence A134819 A134820 A134821
Sequence in context: A018398 A149021 A149022 this_sequence A002751 A119856 A077365
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KEYWORD
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hard,nice,nonn
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AUTHOR
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David A. Consiglio, Jr. (davecons2002(AT)yahoo.com), Jan 28 2008
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EXTENSIONS
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a(8)-a(10) from Vesa Linja-aho (vesa.linja-aho(AT)tkk.fi), Apr 17 2008
a(11) from Vesa Linja-aho (vesa.linja-aho(AT)tkk.fi), Apr 24 2008
a(12) sent by David A. Consiglio, Jr. (davecons2002(AT)yahoo.com), Apr 23 2008
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