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 A055961 #21 Feb 21 2023 17:19:19
%S A055961 0,0,0,0,0,0,0,0,0,0,0,10,0,-10,-20,-30,-40,-50,-60,-70,-80,-90,20,10,
%T A055961 0,-10,-20,-30,-40,-50,-60,-70,-80,30,20,10,0,-10,-20,-30,-40,-50,-60,
%U A055961 -70,40,30,20,10,0,-10,-20,-30,-40,-50,-60,50,40,30,20,10,0,-10,-20,-30,-40,-50,60,50,40,30,20,10,0,-10,-20,-30,-40
%N A055961 a(n) = n - (reversal of base-11 digits of n) (written in base 10).
%C A055961 a(n) is a multiple of 10.
%H A055961 Robert Israel, <a href="/A055961/b055961.txt">Table of n, a(n) for n = 0..10000</a>
%F A055961 a(n) = n - A056960(n).
%p A055961 f:= proc(n) local L,t;
%p A055961 L:= convert(n,base,11);
%p A055961 n - add(L[-i]*11^(i-1),i=1..nops(L))
%p A055961 end proc:
%p A055961 map(f, [$0..100]); # _Robert Israel_, Apr 20 2021
%t A055961 Table[n-FromDigits[Reverse[IntegerDigits[n,11]],11],{n,0,80}] (* _Harvey P. Dale_, Feb 21 2023 *)
%o A055961 (PARI) a(n) = n - fromdigits(Vecrev(digits(n, 11)), 11); \\ _Michel Marcus_, Apr 22 2021
%Y A055961 Cf. A056960 (base-11 reversal), A056965 (n minus decimal reversal).
%K A055961 base,sign,look
%O A055961 0,12
%A A055961 _Henry Bottomley_, Jul 18 2000