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 A288535 #8 Jun 15 2017 17:11:10
%S A288535 1,2,3,2,4,3,2,1,4,3,2,4,6,8,3,2,4,6,5,4,3,2,4,1,8,10,8,7,2,4,6,8,6,
%T A288535 15,4,3,2,4,6,8,10,12,5,14,3,2,4,6,1,10,7,18,10,4,15,2,4,6,8,10,12,14,
%U A288535 24,15,8,3,2,4,6,8,10,12,8,21,6,5,4,15,2,4,6
%N A288535 Array RATS(b,n) by upward antidiagonals: Reverse Add Then Sort digits of n>0 in base b>1.
%H A288535 J. Thiel, <a href="https://www.emis.de/journals/INTEGERS/papers/o50/o50.pdf">On RATS sequences in general bases</a>, Integers, 14 (2014), #A50.
%H A288535 <a href="/index/Ra#RATS">Index entries for sequences related to RATS: Reverse, Add Then Sort</a>
%e A288535 17 in base 3 is 122, 122+221=1120->112 which is 14 in decimal, thus RATS(3,17)=14.
%e A288535 The array begins:
%e A288535 1, 3, 3, 3, 3, 3, 7, ...
%e A288535 2, 4, 4, 8, 4, 8, 4, ...
%e A288535 2, 1, 6, 5, 10, 15, 5, ...
%e A288535 2, 4, 6, 8, 6, 12, 18, ...
%e A288535 2, 4, 1, 8, 10, 7, 14, ...
%t A288535 rats[n_, b_: 10] := FromDigits[Sort[IntegerDigits[n + FromDigits[Reverse[IntegerDigits[n, b]], b], b]], b];
%t A288535 Flatten[Table[rats[n, s + 2 - n], {s, 20}, {n, s}]]
%Y A288535 Cf. A004000, A036839 (row 10), A191780, A288536, A288537.
%K A288535 nonn,tabl,base,easy
%O A288535 2,2
%A A288535 _Andrey Zabolotskiy_, Jun 11 2017