A159941 -id:A159941 - cp's OEIS frontend

A159938 The number of homogeneous trisubstituted linear alkanes.

2, 6, 16, 36, 70, 122, 196, 296, 426, 590, 792, 1036, 1326, 1666, 2060, 2512, 3026, 3606, 4256, 4980, 5782, 6666, 7636, 8696, 9850, 11102, 12456, 13916, 15486, 17170, 18972, 20896, 22946, 25126, 27440, 29892, 32486

Offset: 2

Parthasarathy Nambi, Apr 26 2009

See the paper by Valentin Vankov Iliev for details.

This sequence is related to A152947 by a(n) = (n-1)*A152947(n) + sum( A152947(i), i=1..n-1 ). - Bruno Berselli, Dec 19 2013

			The number of homogeneous trisubstituted linear alkane with ten carbon atoms is 426.

Valentin Vankov Iliev, A mathematical characterization of the groups of substitution isomerism of the linear alkanes, J. Math. Chem. 47 (2010), 52-61.
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Cf. A002522, A033816, A081489, A152947, A159940, A159941.

a(n) = (1/3)*(2*n^3 - 9*n^2 + 19*n - 12), where n is the number of carbons.
a(n) = 2*A081489(n-1) = (n-1)*(2*n^2-7*n+12)/3. - R. J. Mathar, Apr 28 2009
G.f.: 2*x^2*(1-x+2*x^2)/(1-x)^4. - Colin Barker, Aug 06 2012

More terms from Colin Barker, Aug 06 2012

A159940 The number of trisubstitution products with composition C_n H_(2n-1) X_2 Y.

Original entry on oeis.org

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

Offset: 2

Parthasarathy Nambi, Apr 26 2009

See the paper by Valentin Vankov Iliev for details.

			The number of trisubstitution products with composition C_n H_(2n-1) X_2 Y for n = 10 is 1276.

Valentin Vankov Iliev, A mathematical characterization of the groups of substitution isomerism of the linear alkanes, J. Math. Chem. 47 (2010), 52-61.
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Cf. A002522, A033816, A159938, A159941.

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)/(x-1)^4. - R. J. Mathar, Apr 28 2009

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

cp's OEIS Frontend

A159938 The number of homogeneous trisubstituted linear alkanes.

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