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 A348331 #9 Oct 17 2021 15:26:18 %S A348331 1,1,1,2,2,1,3,3,2,4,4,1,5,5,3,6,6,2,7,7,4,8,8,1,9,9,5,10,10,3,11,11, %T A348331 6,12,12,2,13,13,7,14,14,4,15,15,8,16,16,1,17,17,9,18,18,5,19,19,10, %U A348331 20,20,3,21,21,11,22,22,6,23,23,12,24,24,2,25,25,13 %N A348331 Lexicographically earliest sequence of positive integers such that for any n > 0, the sum of the indices k < n such that a(k) = a(n) is less than or equal to n. %C A348331 Every integer appears infinitely many times. %C A348331 See table A348357 where the integers are arranged according to the present sequence. %F A348331 a(n) = 1 iff n belongs to A098011. %o A348331 (PARI) s=vector(25); for (n=1, 75, for (k=1, oo, if (s[k]<=n, print1 (k", "); s[k]+=n; break))) %Y A348331 Cf. A098011, A348330, A348356, A348357. %K A348331 nonn %O A348331 1,4 %A A348331 _Rémy Sigrist_, Oct 13 2021