A036673 Number of stereoisomers of all n-node acyclic hydrocarbons with no triple bonds.

1, 2, 3, 9, 20, 64, 205, 747, 2767, 10850, 43254, 176990, 735007, 3099272, 13220407, 57001841, 248009246, 1087947441, 4807232915, 21381055533, 95660032110, 430298114499, 1945096434552, 8832200860663, 40271358004756, 184325394540531, 846667179332120

Offset

1,2

Comments

Alternatively, unrooted steric quartic trees allowing single and double edges with n nodes. - Natan Arie Consigli, Jun 30 2017

Read has incorrect a(10)=14159. - Sean A. Irvine, Nov 20 2020

Links

Table of n, a(n) for n=1..27.

Sean A. Irvine, Java program (github)

Sean A. Irvine, Correction of A036672(10) and A036673(10), 2020

R. C. Read, The Enumeration of Acyclic Chemical Compounds, pp. 25-61 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976. [Annotated scanned copy] See p. 60.

Crossrefs

Cf. A000628 (steric quartic trees with no double edges).

Sequence in context: A369517 A245123 A097075 * A111189 A001004 A015951

Adjacent sequences: A036670 A036671 A036672 * A036674 A036675 A036676

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Name clarified by Natan Arie Consigli, Jun 30 2017

a(10) corrected and more terms from Sean A. Irvine, Nov 20 2020

Status

approved