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 A330588 #12 Dec 13 2023 11:46:35 %S A330588 0,3,6,13,21,23,27,33,46,67,81,104,107,114,129,166,169,172,193,261, %T A330588 267,276,287,311,373,430,457,478,485,590,596,656,691,768,789,796,873, %U A330588 941,969,1047,1093,1149,1170,1239,1303,1349,1491,1533,1555,1567,1805,1808 %N A330588 a(n) is the first index m such that A330439(m) = n. %H A330588 Alois P. Heinz, <a href="/A330588/b330588.txt">Table of n, a(n) for n = 1..16000</a> %p A330588 b:= proc() 0 end: %p A330588 g:= proc(n) option remember; local t; %p A330588 t:= `if`(n<2, n, b(g(n-1))+b(g(n-2))); %p A330588 b(t):= b(t)+1; t %p A330588 end: %p A330588 f:= proc(n) option remember; b(g(n)) end: %p A330588 a:= proc() local l, t; t, l:= -1, proc() -1 end; %p A330588 proc(k) local h; %p A330588 while l(k)<0 do t:= t+1; h:= f(t); %p A330588 if l(h)<0 then l(h):= t fi %p A330588 od: l(k) %p A330588 end %p A330588 end(): %p A330588 seq(a(n), n=1..60); %t A330588 b[_] = 0; %t A330588 g[n_] := g[n] = Module[{t}, t = If[n < 2, n, b[g[n-1]] + b[g[n-2]]]; b[t]++; t]; %t A330588 f[n_] := f[n] = b[g[n]]; %t A330588 A[n_, k_] := Module[{l, t = -1, h}, l[_] = {}; While[Length[l[k]] < n, t++; h = f[t]; AppendTo[l[h], t]]; l[k][[n]]]; %t A330588 a[k_] := A[1, k]; %t A330588 Table[a[n], {n, 1, 60}] (* _Jean-François Alcover_, Dec 13 2023, after _Alois P. Heinz_ *) %Y A330588 Row n=1 of A330587. %Y A330588 Cf. A316774, A330439. %K A330588 nonn %O A330588 1,2 %A A330588 _Alois P. Heinz_, Dec 18 2019