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 A108408 #7 May 11 2023 14:27:09
%S A108408 1,2,3,4,6,8,9,10,12,14,15,16,17,18,22,23,24,25,27,28,29,30,31,32,33,
%T A108408 34,35,36,38,39,40,41,42,43,44,45,46,47,49,52,53,54,55,56,57,58,59,60,
%U A108408 62,63,64,66,67,69,70,71,72,73,74,77,78,79,82,83,84,85,86,87,88,89,90
%N A108408 Unique values found in A108407. Complement of A108409.
%t A108408 terms = 71;
%t A108408 nmax = 3 terms;
%t A108408 A062854 = Table[u = If[n == 1, {}, Union[u, n Range[n]]]; Length[u], {n, 1, nmax + 1}] // Differences // Prepend[#, 1]&;
%t A108408 a108407[n_] := n + 1 - A062854[[n+1]];
%t A108408 Array[a108407, nmax] // Union // Rest // Take[#, terms]& (* _Jean-François Alcover_, Oct 02 2020 *)
%Y A108408 Cf. A108407, A108409.
%K A108408 nonn
%O A108408 1,2
%A A108408 _Ralf Stephan_, Jun 03 2005