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 A180019 #9 Nov 06 2022 07:48:42 %S A180019 0,0,0,2,2,2,4,4,4,8,-1,-1,1,1,1,3,3,3,7,7,-2,0,0,0,2,2,2,8,8,8,1,1,1, %T A180019 3,3,3,7,7,7,9,0,0,2,2,2,6,6,6,8,8,-1,1,1,1,7,7,7,9,9,9,2,2,2,6,6,6,8, %U A180019 8,8,10,1,1,5,5,5,7,7,7,9,9,0,8,8,8,10,10,10,12,12,12,7,7,7,9,9,9,11,11,11 %N A180019 Difference of sums of digits of n in decimal and in ternary representation. %H A180019 Reinhard Zumkeller, <a href="/A180019/b180019.txt">Table of n, a(n) for n = 0..10000</a> %H A180019 <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a> %F A180019 a(n) = A007953(n) - A053735(n); %F A180019 a(A037315(n)) = 0; %F A180019 a(A011557(n)) = 1 - A053735(A011557(n)); %F A180019 a(A000244(n)) = A007953(A000244(n)) - 1; %F A180019 a(A002283(n)) = A008591(n) - A053735(A002283(n)); %F A180019 a(A024023(n)) = A007953(A024023(n)) - 2*n. %o A180019 (PARI) a(n) = sumdigits(n) - sumdigits(n, 3); \\ _Michel Marcus_, Nov 06 2022 %Y A180019 Cf. A180017, A180018, A007089. %Y A180019 Cf. A007953, A053735, A037315, A011557. %Y A180019 Cf. A000244, A002283, A008591, A024023. %K A180019 base,sign %O A180019 0,4 %A A180019 _Reinhard Zumkeller_, Aug 06 2010