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 A131984 #7 Apr 27 2024 01:58:26
%S A131984 1,4,6,8,10,12,18,20,24,30,36,48,60,84,90,120,168,180,240,336,360,420,
%T A131984 480,540,600,660,720,840,1080,1260,1440,1680,2160,2520,3360,3780,4200,
%U A131984 4620,5040,7560,9240,10080,12600,13860,15120,18480,20160,25200,27720
%N A131984 Where records occur in A106708.
%C A131984 Numbers n such that concatenation of proper divisors of n exceeds that of all smaller numbers. Empty concatenation is regarded as 0.
%C A131984 Sequence has many terms in common with A034090 (numbers n such that sum of proper divisors of n exceeds that of all smaller numbers), A034287 (numbers n such that product of divisors of n is larger than for any number less than n), A034288 (product of proper divisors is larger than for any smaller number), A067128 (Ramanujan's largely composite numbers, defined to be n such that d(n) >= d(k) for k = 1 to n-1).
%H A131984 Klaus Brockhaus, <a href="/A131984/b131984.txt">Table of n, a(n) for n=1..144 </a>
%t A131984 DeleteDuplicates[Table[{n,If[CompositeQ[n],FromDigits[Flatten[IntegerDigits/@Rest[ Most[ Divisors[n]]]]],0]},{n,30000}],GreaterEqual[#1[[2]],#2[[2]]]&][[;;,1]] (* _Harvey P. Dale_, Apr 27 2024 *)
%o A131984 (PARI) {map(n) = local(d); d=divisors(n); if(#d<3, 0, d[1]=""; eval(concat(vecextract(d, concat("..", #d-1)))))} {m=28000; r=-1; for(n=1, m, if(r<(a=map(n)), r=a; print1(n, ",")))}
%Y A131984 Cf. A106708, A131983 (records), A034090, A034287, A034288, A067128.
%K A131984 nonn,base
%O A131984 1,2
%A A131984 _Klaus Brockhaus_, Aug 05 2007