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 A076424 #3 Mar 30 2012 17:27:39
%S A076424 1,2,3,12,31,23,56,102,193,257,570,1129,4970,3229,11551,11969,24232,
%T A076424 20094,24103,35996,100090,222284,116269,231488,388768,1751753,2046872,
%U A076424 1140163,1149979,2156214,3199384,2971734,7018074,10163234,13135933
%N A076424 Smallest number that requires n steps to reach 0 when iterating the mapping k -> abs(reverse(lpd(k))-reverse(Lpf(k))). lpd(k) is the largest proper divisor and Lpf(k) is the largest prime factor of k.
%e A076424 a(5) =31 since 31 requires 5 steps, but no m < 31 does. Although 23 < 31, 23 requires 6 steps.
%o A076424 (PARI) {m=36; z=19200000; v=listcreate(m); for(i=1,m,listinsert(v,-1,i)); for(n=1,z,c=1; b=1; k=n; while(b&&c<=m, d=divisors(k); i=matsize(d)[2]-1; z=if(i>0,d[i],1); p=0; while(z>0,d=divrem(z,10); z=d[1]; p=10*p+d[2]); z= if(k==1,1,vecmax(component(factor(k),1))); q=0; while(z>0,d=divrem(z,10); z=d[1]; q=10*q+d[2]); a= abs(p-q); if(a==0,b=0,k=a; c++)); if(a==0,if(v[c]<0,v[c]=n; print1([c,n])))); print(); for(i=1,m,print1(v[i],","))}
%Y A076424 Cf. A074347, A076423.
%K A076424 base,nonn
%O A076424 1,2
%A A076424 _Klaus Brockhaus_, Oct 11 2002