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 A336576 #8 Aug 02 2020 03:42:35 %S A336576 59,947,313,3331,5659,67547,253801,676259,3162413,16604417,29135971, %T A336576 108235159,437456497 %N A336576 The final square number for a walk on a square spiral numbered board when starting on square 1 and stepping to an unvisited square containing the lowest prime number, where the square is within a block of size (2n+1) x (2n+1) centered on the current square. If no unvisited prime numbered squares exist within the block the walk ends. %C A336576 See A336494 for an explanation of the sequence and images of the walks. %H A336576 Wikipedia, <a href="https://en.wikipedia.org/wiki/Ulam_spiral">Ulam Spiral</a>. %e A336576 a(1) = 59. Starting from the square 1 the sequence of adjacent unvisited lowest primes the walk can step to are 2,3,11,29,13,31,59. Once the square 59 is visited there are no other unvisited adjacent squares containing primes, so the walk terminates. %Y A336576 Cf. A336494 (total number of steps), A335856, A000040, A136626, A336092, A330979, A332767, A335661, A335364. %K A336576 nonn,walk,more %O A336576 1,1 %A A336576 _Scott R. Shannon_, Jul 26 2020