This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A159938 #14 Dec 01 2021 12:36:58 %S A159938 2,6,16,36,70,122,196,296,426,590,792,1036,1326,1666,2060,2512,3026, %T A159938 3606,4256,4980,5782,6666,7636,8696,9850,11102,12456,13916,15486, %U A159938 17170,18972,20896,22946,25126,27440,29892,32486 %N A159938 The number of homogeneous trisubstituted linear alkanes. %C A159938 See the paper by Valentin Vankov Iliev for details. %C A159938 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 %H A159938 Valentin Vankov Iliev, <a href="https://doi.org/10.1007/s10910-009-9534-4">A mathematical characterization of the groups of substitution isomerism of the linear alkanes</a>, J. Math. Chem. 47 (2010), 52-61. %H A159938 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1). %F A159938 a(n) = (1/3)*(2*n^3 - 9*n^2 + 19*n - 12), where n is the number of carbons. %F A159938 a(n) = 2*A081489(n-1) = (n-1)*(2*n^2-7*n+12)/3. - _R. J. Mathar_, Apr 28 2009 %F A159938 G.f.: 2*x^2*(1-x+2*x^2)/(1-x)^4. - _Colin Barker_, Aug 06 2012 %e A159938 The number of homogeneous trisubstituted linear alkane with ten carbon atoms is 426. %Y A159938 Cf. A002522, A033816, A081489, A152947, A159940, A159941. %K A159938 nonn,easy %O A159938 2,1 %A A159938 _Parthasarathy Nambi_, Apr 26 2009 %E A159938 More terms from _Colin Barker_, Aug 06 2012