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 A341327 #8 Feb 12 2021 11:37:59 %S A341327 6,19,28,29,53,54,61,62,63,86,87,114,115,116,117,161,162,163,164,185, %T A341327 186,187,188,189,227,228,229,230,231,232,244,245,246,247,248,311,312, %U A341327 313,314,315,407,408,409,410,411,412,413,771,772,773,774,775,776,777,778,779,866,867,868,869,870,871 %N A341327 The spiral numbers not covered by any square in the square spiral tiling of A341160. %C A341327 See A341160 for an image of the square spiral tiling which shows the uncovered numbers in black. %e A341327 a(1) = 6 and a(2) = 19 as the first, third, fourth, and seventh square of A341160 cover the numbers (1), (5,18), (7,20), (40) respectively which leaves a gap containing numbers 6 and 19 which cannot be covered by any subsequence square. %Y A341327 Cf. A341160, A340974, A174344, A274923, A296030, A275161. %K A341327 nonn %O A341327 1,1 %A A341327 _Scott R. Shannon_, Feb 09 2021