

A159940


The number of trisubstitution products with composition C_n H_(2n1) X_2 Y.


1



4, 16, 46, 106, 208, 364, 586, 886, 1276, 1768, 2374, 3106, 3976, 4996, 6178, 7534, 9076, 10816, 12766, 14938, 17344, 19996, 22906, 26086, 29548, 33304, 37366, 41746, 46456, 51508, 56914, 62686, 68836, 75376, 82318, 89674, 97456, 105676, 114346
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OFFSET

2,1


COMMENTS

See the paper by Valentin Vankov Iliev for details.


REFERENCES

Valentin Vankov Iliev, "A mathematical characterization of the groups of substitution isomerism of the linear alkanes", J. Math. Chem., 45 (2009), xxxyyy. Page numbers unknown as of today as it is an 'online first' article.


LINKS

Table of n, a(n) for n=2..40.


FORMULA

a(n) = (2 n^3  9 n^2 + 19 n  14) where n is the number of carbons.
G.f.: 2*x^2*(2+3*x^2+x^3)/(x1)^4. [From R. J. Mathar, Apr 28 2009]


EXAMPLE

The number of trisubstitution products with composition C_n H_(2n1) X_2 Y for n = 10 is 1276.


CROSSREFS

Cf. A002522, A033816
Sequence in context: A097125 A213480 A306302 * A000704 A007315 A055342
Adjacent sequences: A159937 A159938 A159939 * A159941 A159942 A159943


KEYWORD

nonn


AUTHOR

Parthasarathy Nambi, Apr 26 2009


EXTENSIONS

More terms from R. J. Mathar, Apr 28 2009


STATUS

approved



