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 A351686 #16 Jun 11 2022 13:52:05 %S A351686 13,23,31,41,53,61,73,97,103 %N A351686 Solution to stepping stone puzzle if we start with one 1 and n 2's for consecutive primes. %C A351686 Start with an infinite square grid. Each cell has eight neighbors. Place one 1 and n 2's anywhere. Now place the prime numbers 3, 5, 7, ..., m in order, subject to the rule that when you place k, the sum of its neighbors must equal k. Then a(n) is the maximum m that can be achieved. %H A351686 Rodolfo Kurchan, <a href="http://www.puzzlefun.online/problems">Puzzle Fun</a>, Forest of Numbers. %H A351686 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_1079.htm">Puzzle 1079. Forest of Prime Numbers</a>, The Prime Puzzles & Problems Connection, March 2022. %e A351686 Illustration for a(1) with 1 stone = 13 from Rodolfo Kurchan %e A351686 . . 1 %e A351686 . 11 3 %e A351686 13 2 5 %e A351686 . . 7 %e A351686 a(2) with 2 stones = 23 from Rodolfo Kurchan %e A351686 . . 1 23 . %e A351686 . 11 3 . 19 %e A351686 13 2 5 17 2 %e A351686 . . 7 . . %e A351686 a(3) with 3 stones = 31 from Rodolfo Kurchan %e A351686 . . 1 23 . %e A351686 . 11 3 . 19 %e A351686 13 2 5 17 2 %e A351686 . 29 7 31 . %e A351686 2 . . . . %e A351686 a(4) with 4 stones = 41 from Dmitry Kamenetsky %e A351686 . 2 37 31 . 1 . %e A351686 23 2 . 2 29 . 3 %e A351686 . 19 17 13 11 2 5 %e A351686 . . . 41 . 7 . %e A351686 a(5) with 5 stones = 53 from Giorgio Vecchi %e A351686 -- 47 -- 31 -- %e A351686 43 02 02 29 -- %e A351686 41 -- 23 03 01 %e A351686 02 37 05 11 -- %e A351686 -- 07 -- 02 13 %e A351686 -- -- -- 17 53 %e A351686 -- -- -- 19 02 %e A351686 a(6) with 6 stones = 61 from Giorgio Vecchi %e A351686 -- -- -- 31 02 02 61 -- %e A351686 -- -- -- -- 29 -- 59 -- %e A351686 -- 47 37 23 -- 02 53 02 %e A351686 03 02 05 07 11 13 17 19 %e A351686 -- 01 -- 02 -- 41 -- -- %e A351686 -- -- -- -- 43 -- -- -- %e A351686 a(7) with 7 stones = 73 from Giorgio Vecchi %e A351686 -- -- -- -- -- -- 61 -- 47 -- -- %e A351686 -- 07 -- 71 -- 59 -- 02 02 43 02 %e A351686 02 05 41 13 17 19 23 29 02 37 -- %e A351686 -- 03 11 02 53 02 73 -- 31 -- -- %e A351686 -- -- 01 67 -- -- -- -- -- -- -- %e A351686 a(8) with 8 stones = 89 from Giorgio Vecchi %e A351686 -- -- -- -- 19 02 73 -- -- %e A351686 -- -- -- -- 17 -- -- 71 -- %e A351686 -- -- 29 13 02 23 02 67 02 %e A351686 07 05 11 59 -- 31 02 61 -- %e A351686 -- 02 03 01 -- 37 02 53 -- %e A351686 -- -- 89 83 79 41 02 47 -- %e A351686 -- -- -- -- -- -- 43 -- -- %e A351686 a(9) with 9 stones = 97 from Dmitry Kamenetsky %e A351686 -- -- -- -- -- 61 -- -- %e A351686 -- -- -- -- -- 59 02 -- %e A351686 -- -- -- 67 02 02 53 19 %e A351686 -- 02 11 47 07 13 17 89 %e A351686 -- 05 03 01 23 02 -- -- %e A351686 -- -- 71 29 -- -- -- -- %e A351686 -- 73 02 31 97 -- -- -- %e A351686 -- 79 -- 37 -- -- -- -- %e A351686 02 83 02 41 02 -- -- -- %e A351686 -- -- -- -- 43 -- -- -- %e A351686 a(10) with 10 stones = 103 from Giorgio Vecchi %e A351686 -- -- -- -- 103 02 -- %e A351686 -- -- -- -- 101 -- 47 %e A351686 -- 02 -- 97 -- 02 43 %e A351686 -- 23 29 31 37 41 -- %e A351686 19 02 -- 02 -- 02 -- %e A351686 17 53 59 61 67 02 -- %e A351686 13 02 -- -- -- 71 -- %e A351686 11 -- 05 89 02 73 -- %e A351686 02 07 -- 03 79 -- -- %e A351686 -- -- -- 83 01 -- -- %Y A351686 Cf. A337663. %K A351686 nonn,more %O A351686 1,1 %A A351686 _Rodolfo Kurchan_, May 04 2022