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 A127500 #12 Sep 07 2015 13:20:52 %S A127500 5,9,9,12,13,16,18 %N A127500 On the triangular peg solitaire board of side n, the shortest solution to any problem beginning with one peg missing and ending with one peg. %C A127500 Shortest means the minimum number of moves, where a move is one or more jumps by the same peg. The reference calculates a(n) up to n=10 and gives the bounds 19<=a(11)<=28, 21<=a(12)<=29, as well as an upper bound for n a multiple of 12. A trivial upper bound is a(n)<=T(n)-2, where T(n) is the n-th triangular number. %D A127500 Martin Gardner, Penny Puzzles, in Mathematical Carnival, p. 12-26, Alfred A. Knopf, Inc., 1975 %H A127500 George I. Bell, <a href="http://home.comcast.net/~gibell/pegsolitaire/">Triangular Peg Solitaire</a>. %H A127500 George I. Bell, <a href="http://arXiv.org/abs/math.CO/0703865">Solving Triangular Peg Solitaire</a> [arXiv:math/0703865v4] %H A127500 G. I. Bell, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL11/Bell/bell2.html">Solving Triangular Peg Solitaire</a>, JIS 11 (2008) 08.4.8 %e A127500 a(4)=5, the 10-hole triangular board can be solved in 5 moves (and always 8 jumps). %Y A127500 Cf. A000217, A102422. %K A127500 hard,more,nonn %O A127500 4,1 %A A127500 George Bell (gibell(AT)comcast.net), Mar 31 2007