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 A325693 #13 Sep 10 2019 14:16:35 %S A325693 0,1,2,3,4,5,13,7,8,9,10,11,12,20,14,15,16,17,18,19,27,21,22,23,24,25, %T A325693 26,34,28,29,30,31,32,33,41,35,36,37,38,39,40,48,42,43,44,45,46,96,55, %U A325693 49,50,51,52,53,54,62,56,57,58,59,60,61,69,63,64,65,66,67,68,76,70,71 %N A325693 "Sloping septenary numbers": write numbers in septenary under each other (right-justified), read diagonals in upward direction, convert to decimal. %H A325693 Seiichi Manyama, <a href="/A325693/b325693.txt">Table of n, a(n) for n = 0..10000</a> %Y A325693 Cf. A102370 (base 2), A109681 (base 3), A325644 (base 4), A325645 (base 5), A325692 (base 6), this sequence (base 7), A325805 (base 8), A325829 (base 9), A103205 (base 10). %K A325693 nonn,base %O A325693 0,3 %A A325693 _Seiichi Manyama_, Sep 07 2019