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 A359861 #13 Oct 11 2024 07:56:17 %S A359861 4,84,420,1604,3904,8444,15524,27356,43540,67720,99088,142912,196820, %T A359861 267580,352844,460432,586592,741852,920528,1136888,1382360,1672384, %U A359861 1998964,2380940,2804292,3291376,3830048,4444176,5116128,5876580,6703220,7631352,8634796,9751064,10956320 %N A359861 Number of edges among all distinct circles that can be constructed from a 2 X n square grid of points using only a compass. %C A359861 See A359859 and A359860 for further details and images of the circles. No formula for a(n) is known. %H A359861 Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/A359859%2B60%2B61.py">Python program</a>. %e A359861 a(n) = A359859(n) + A359860(n) - 1 by Euler's formula. %Y A359861 Cf. A359859 (vertices), A359860 (regions), A359862 (k-gons), A001859, A359254. %K A359861 nonn %O A359861 1,1 %A A359861 _Scott R. Shannon_, Jan 16 2023 %E A359861 a(19)-a(35) from _Lucas A. Brown_, Oct 11 2024