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 A154234 #18 Sep 07 2016 00:17:29
%S A154234 0,0,0,0,1,1,0,0,0,1,0,1,1,2,1,0,0,0,0,0,2,0,1,1,1,1,3,1,0,0,0,2,0,0,
%T A154234 0,0,0,1,1,0,1,1,1,1,0,0,0,0,1,0,2,0,2,1,2,0,1,1,2,1,3,1,3,2,3,1,0,0,
%U A154234 0,0,0,0,0,0,0,0,0,0,0,1,1
%N A154234 Triangle read by rows: T(n,k) = (n mod d(k)), where d(i) is the number of divisors of i.
%H A154234 G. C. Greubel, <a href="/A154234/b154234.txt">Table of n, a(n) for the first 50 rows</a>
%e A154234 The first few rows are given by:
%e A154234 0.
%e A154234 0 0.
%e A154234 0 1 1.
%e A154234 0 0 0 1.
%e A154234 0 1 1 2 1.
%e A154234 0 0 0 0 0 2.
%e A154234 0 1 1 1 1 3 1.
%e A154234 0 0 0 2 0 0 0 0.
%e A154234 0 1 1 0 1 1 1 1 0.
%e A154234 0 0 0 1 0 2 0 2 1 2.- _G. C. Greubel_, Sep 06 2016
%t A154234 Table[Mod[n,DivisorSigma[0,k]],{n,20},{k,n}]//Flatten (* _Harvey P. Dale_, Jul 21 2016 *)
%o A154234 (PARI) T(n,k)=n%numdiv(k) \\ _Charles R Greathouse IV_, Sep 07 2016
%Y A154234 Cf. A000005.
%K A154234 nonn,tabl,easy
%O A154234 1,14
%A A154234 _Juri-Stepan Gerasimov_, Nov 26 2010