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 A073794 #7 Dec 09 2020 01:53:37
%S A073794 0,1,2,3,4,5,6,-7,-6,-5,-4,-3,-2,-1,-14,-13,-12,-11,-10,-9,-8,-21,-20,
%T A073794 -19,-18,-17,-16,-15,-28,-27,-26,-25,-24,-23,-22,-35,-34,-33,-32,-31,
%U A073794 -30,-29,-42,-41,-40,-39,-38,-37,-36,49,50,51,52,53,54,55,42,43,44,45,46,47,48,35,36,37,38,39,40,41
%N A073794 Replace 7^k with (-7)^k in base 7 expansion of n.
%C A073794 Base 7 representation for n (in lexicographic order) converted from base -7 to base 10.
%H A073794 Dana G. Korssjoen, Biyao Li, Stefan Steinerberger, Raghavendra Tripathi, and Ruimin Zhang, <a href="https://arxiv.org/abs/2012.04625">Finding structure in sequences of real numbers via graph theory: a problem list</a>, arXiv:2012.04625, Dec 08, 2020
%F A073794 a(7*k+m) = -7*a(k)+m for 0 <= m < 7. - _Chai Wah Wu_, Jan 16 2020
%t A073794 f[n_Integer, b_Integer] := Block[{l = IntegerDigits[n]}, Sum[l[[ -i]]*(-b)^(i - 1), {i, 1, Length[l]}]]; a = Table[ FromDigits[ IntegerDigits[n, 7]], {n, 0, 80}]; b = {}; Do[b = Append[b, f[a[[n]], 7]], {n, 1, 80}]; b
%Y A073794 Cf. A007093, A073788, A053985, A065369, A073791, A073792, A073793, A073795, A073796 & A073835.
%K A073794 base,easy,sign
%O A073794 0,3
%A A073794 _Robert G. Wilson v_, Aug 12 2002