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 A112426 #26 Jun 02 2025 16:32:19
%S A112426 0,0,0,0,0,1,9,134,1714,18436,167703,1327240,9372119,60324933,
%T A112426 359730035,2012733260,10670975762,54028108819,262872075003,
%U A112426 1235323112178,5630370812614
%N A112426 Number of connected simple graphs with n vertices, n+6 edges, and vertex degrees no more than 4.
%C A112426 Distribution of carbon skeletons. See the paper by Hendrikson and Parks for details. If n=6 the number of 7-cyclic skeletons is 1. If n=7 the number of 7-cyclic skeletons is 9. If n=10 the number of 7-cyclic skeletons is 18436. - _Parthasarathy Nambi_, Jan 05 2007
%H A112426 J. B. Hendrickson and C. A. Parks, <a href="https://doi.org/10.1021/ci00001a018">Generation and Enumeration of Carbon skeletons</a>, J. Chem. Inf. Comput. Sci., 31 (1991), 101-107. See Table 2, column 7 on page 103.
%H A112426 Michael A. Kappler, <a href="http://www.daylight.com/meetings/emug04/Kappler/GenSmi.html">GENSMI: Exhaustive Enumeration of Simple Graphs</a> [gives different numbers for n > 10].
%o A112426 (nauty)
%o A112426 for n in {6..13}; do geng -c -D4 ${n} $((n+6)):$((n+6)) -u; done # _Andrey Zabolotskiy_, Nov 24 2017
%Y A112426 The analogs for n+k edges with k = -1, 0, ..., 7 are: A000602, A036671, A112410, A112619, A112408, A112424, A112425, this sequence, A112442. Cf. A121941.
%K A112426 nonn,more
%O A112426 1,7
%A A112426 _Jonathan Vos Post_, Dec 21 2005
%E A112426 New name, offset corrected, and a(11)-a(14) corrected by _Andrey Zabolotskiy_, Nov 24 2017
%E A112426 a(15)-a(21) added by _Georg Grasegger_, Jun 05 2023