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 A341278 #15 Feb 14 2021 13:17:47 %S A341278 67,173,25,30,42,56,72,90,110,132,156,182,209,239,271,305,341,379,419, %T A341278 461,505,551,599,649,701,755,810,860,928,990,1054,1120,1188,1258,1330, %U A341278 1404,1480,1558,1638,1720,1804,1890,1978,2067,2159,2253,2349,2447,2547,2649,2753,2859,2967,3077,3189 %N A341278 The smallest spiral number not covered by any square in the minimal-sum square spiral tiling by n X n squares in A341363. %C A341278 The tilings with n=2 and n=3 are the only ones where the smallest uncovered square is not adjacent to the first centrally placed tile. The sequence starts at n=2 as a 1 X 1 square tiling leaves no squares uncovered. %C A341278 See A341363 for other images with higher numbers of placed tiles. %H A341278 Scott R. Shannon, <a href="/A341278/a341278.png">Image of the tiling for n=2</a>. The smallest uncovered square is 67. In this and other images the colors are graduated around the spectrum to show the squares relative placement order. %H A341278 Scott R. Shannon, <a href="/A341278/a341278_1.png">Image of the tiling for n=3</a>. The smallest uncovered square is 173. %H A341278 Scott R. Shannon, <a href="/A341278/a341278_2.png">Image of the tiling for n=4</a>. The smallest uncovered square is 25. %H A341278 Scott R. Shannon, <a href="/A341278/a341278_3.png">Image of the tiling for n=5</a>. The smallest uncovered square is 30. %H A341278 Scott R. Shannon, <a href="/A341278/a341278_4.png">Image of the tiling for n=6</a>. The smallest uncovered square is 42. %Y A341278 Cf. A341363, A341160, A341327, A340974, A174344, A274923, A296030, A275161. %K A341278 nonn %O A341278 2,1 %A A341278 _Scott R. Shannon_, Feb 08 2021