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 A048180 #15 Mar 07 2020 00:03:40 %S A048180 1,4,24,131,663,3252,15772,75415,359307,1711908,8191607,39500169, %T A048180 192525021,950868860,4769060224,24331970791,126457607026,670143402073, %U A048180 3623530476832,19998343352758,112668088476243,647904733883526 %N A048180 Number of graphs with n nodes and n+2 edges. %D A048180 J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 146. %H A048180 Sean A. Irvine, <a href="/A048180/b048180.txt">Table of n, a(n) for n = 4..36</a> %H A048180 M. L. Stein and P. R. Stein, <a href="http://dx.doi.org/10.2172/4180737">Enumeration of Linear Graphs and Connected Linear Graphs up to p = 18 Points</a>. Report LA-3775, Los Alamos Scientific Laboratory of the University of California, Los Alamos, NM, Oct 1967 %Y A048180 Cf. A008406. %K A048180 nonn,easy %O A048180 4,2 %A A048180 _N. J. A. Sloane_ %E A048180 More terms from _Vladeta Jovovic_, Jan 03 2000 %E A048180 More terms from _Sean A. Irvine_, Jun 07 2017