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 A342947 #10 Apr 16 2021 00:12:00 %S A342947 1,9,4,3,13,7,5,10,26,18,11,30,37,48,22,31,38,46,58,49,41,52,27,33,40, %T A342947 51,60,70,57,67,81,93,106,123,79,68,82,71,61,74,64,36,65,78,118,77,88, %U A342947 100,85,97,110,124,139,155,172,193,138,154,212,232,256,191,213 %N A342947 Squares visited by the black knight when a white knight and a black knight are moving on a diagonally numbered board, always to the lowest available unvisited square; white moves first. %C A342947 Board is numbered as follows: %C A342947 1 2 4 7 11 16 . %C A342947 3 5 8 12 17 . %C A342947 6 9 13 18 . %C A342947 10 14 19 . %C A342947 15 20 . %C A342947 21 . %C A342947 . %C A342947 Both knights start on square 1, white moves to the lowest unvisited square (8), black then moves to the lowest unvisited square (9) and so on... %C A342947 This sequence is finite, on the black knight's 5503rd step, square 3828 is visited, after which there are no unvisited squares within one knight move. %o A342947 (Python) # see program in A342948 %o A342947 A342947_lst = A342948_lst[::2] # _Michael S. Branicky_, Mar 30 2021 %Y A342947 Cf. A338288, A338289, A338290, A342946, A342948. %K A342947 nonn,fini %O A342947 1,2 %A A342947 _Andrew Smith_, Mar 30 2021