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 A306640 #17 Mar 05 2019 01:43:27 %S A306640 3,6,2,7,4,3,20,8,3,2,13,20,5,6,3,21,7,10,4,4,2,15,42,7,6,9,3,3,54,16, %T A306640 21,12,5,8,6,2,41,13,13,42,7,20,5,4,3,110,40,27,16,14,6,20,4,3,2,27, %U A306640 55,21,54,23,8,13,10,9,6,3,156,25,55,11 %N A306640 Array read by antidiagonals: A(n,k) (n,k >= 2) is the base-n state complexity of the partitioned finite deterministic automaton (PFDA) for the periodic sequence (123..k)*. %C A306640 Rows are ultimately periodic. %H A306640 Charlie Neder, <a href="/A306640/b306640.txt">First 45 antidiagonals, flattened</a> %H A306640 Klaus Sutner and Sam Tetruashvili, <a href="http://www.cs.cmu.edu/~sutner/papers/auto-seq.pdf">Inferring Automatic Sequences</a>. %F A306640 A(n,n^k) = Sum_{i=0..k} n^i. %F A306640 A(n+1,n) = n. %F A306640 It also appears that A(n-1,n) = 2n. %e A306640 Array begins: %e A306640 3 2 3 2 3 %e A306640 6 4 3 6 4 %e A306640 7 8 5 4 9 ... %e A306640 20 20 10 6 5 %e A306640 13 7 7 12 7 %e A306640 ... %Y A306640 Columns: A217519-A217521 (n = 2-4), A247566-A247581 (n = 5-20). %Y A306640 Rows: A217515-A217518 (k = 3-6), A247387-A247391 (k = 7-11), A247434-A247442 (k = 12-20). %K A306640 nonn,tabl %O A306640 1,1 %A A306640 _Charlie Neder_, Mar 02 2019