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 A318873 #6 Sep 16 2018 21:43:23
%S A318873 1,1,3,1,1,1,4,2,2,1,1,1,11,1,7,1,3,12,4,4,1,1,1,1,1,1,1,1,1,1,13,19,
%T A318873 1,1,1,1,1,1,7,17,1,1,19,1,1,1,1,1,1,1,1,1,1,1,17,1,1,1,8,1,1,1,20,9,
%U A318873 4,4,4,4,4,4,4,4,4,1,1,1,1,1,1,1,1,1,1,1,1,16,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,25
%N A318873 First differences of A316156.
%H A318873 Antti Karttunen, <a href="/A318873/b318873.txt">Table of n, a(n) for n = 1..20000</a>
%F A318873 a(n) = A316156(n+1) - A316156(n).
%o A318873 (PARI)
%o A318873 up_to = 20000;
%o A318873 povisin(v,n) = { forstep(j=n,1,-1, if(v[j] == n, return(j))); (0); }; \\ Here: povisin = position_of_n_in_strictly_increasing_v
%o A318873 A318873list(up_to) = { my(v316156 = vector(1+up_to), v318872 = vector(1+up_to), v318873 = vector(up_to), k, s); v316156[1] = v318872[1] = 1; for(n=2, up_to+1, k = 1+v316156[n-1]; if(povisin(v316156, n-1), s = v318872[n-1]; while((s+k)%(n-1), k++)); v316156[n] = k; v318872[n] = v318872[n-1] + v316156[n]; v318873[n-1] = v316156[n] - v316156[n-1]); (v318873); };
%o A318873 v318873 = A318873list(up_to);
%o A318873 A318873(n) = v318873[n];
%Y A318873 Cf. A316156.
%K A318873 nonn
%O A318873 1,3
%A A318873 _Antti Karttunen_, Sep 16 2018