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 A031007 #24 Apr 10 2020 07:46:56
%S A031007 0,1,2,3,4,5,6,0,1,1,1,2,1,3,1,4,1,5,1,6,1,0,2,1,2,2,2,3,2,4,2,5,2,6,
%T A031007 2,0,3,1,3,2,3,3,3,4,3,5,3,6,3,0,4,1,4,2,4,3,4,4,4,5,4,6,4,0,5,1,5,2,
%U A031007 5,3,5,4,5,5,5,6,5,0,6,1,6,2,6,3,6,4,6,5,6,6,6
%N A031007 Triangle T(n,k): Write n in base 7, reverse order of digits, to get row n.
%t A031007 Flatten[Table[Reverse[IntegerDigits[n,7]],{n,0,50}]] (* _Harvey P. Dale_, Feb 25 2014 *)
%o A031007 (PARI) A031007(n, k=-1)={k<0&&error("Flattened sequence not yet implemented.");n\7^k%7} \\ Assuming that columns start with k=0 as in A030308, A030341, ... TO DO: implement flattened sequence, such that A030567(n)=a(n). - _M. F. Hasler_, Jul 21 2013
%Y A031007 Cf. A030308, A030341, A030386, A031235, A030567, A031045, A031087, A031298 for the base-2 to base-10 analogs.
%K A031007 nonn,base,tabf,less
%O A031007 0,3
%A A031007 _Clark Kimberling_
%E A031007 Initial 0 and better name by _Philippe Deléham_, Oct 20 2011