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 A039660 #12 Jul 08 2025 22:39:33 %S A039660 0,0,0,1,2,8,14,43,72,204,336,926,1516,4144,6772,18504,30236,82844, %T A039660 135452,372581,609710,1684220,2758730,7652531,12546332,34941752, %U A039660 57337172,160280987,263224802,738363872,1213502942,3414804517 %N A039660 Related to enumeration of edge-rooted catafusenes. %C A039660 Let b(n>=0) = 0, 0, 0, 0, 1, 0, 6, 0, 29, 0, 132, 0, 590, 0, 2628, ... be the %C A039660 "aerated" version of A045445. This sequence is the convolution of A040000 and b. - _R. J. Mathar_, Jul 30 2019 %H A039660 S. J. Cyvin et al., <a href="https://doi.org/10.1021/ci00009a021">Enumeration and classification of benzenoid systems. 32. Normal perifusenes with two internal vertices</a>, J. Chem. Inform. Comput. Sci., 32 (1992), 532-540. %F A039660 G.f.: (1+x)[1-6x^2+7x^4-(1-3x^2)sqrt(1-6x^2+5x^4)]/[2x^4(1-x)] (eq. (11) in Cyvin et al.) %K A039660 nonn %O A039660 1,5 %A A039660 _N. J. A. Sloane_ %E A039660 More terms from _Emeric Deutsch_, Mar 14 2004