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 A330735 #6 Jan 10 2020 18:13:36 %S A330735 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,6,0,0,0,0,0,0,0,0,0,0, %T A330735 0,0,0,0,0,0,0,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, %U A330735 21,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,6,0,0,0,0,0,0,0,0,0,15,0,0,0,0,3 %N A330735 a(n) = n mod A309639(n), where A309639(n) is the index of the least harmonic number H_i whose denominator (A002805) is divisible by n. %H A330735 Antti Karttunen, <a href="/A330735/b330735.txt">Table of n, a(n) for n = 1..65537</a> %F A330735 a(n) = n mod A309639(n). %o A330735 (PARI) A330735(n) = (n%A309639(n)); %Y A330735 Cf. A309639, A330691, A330692, A330734, A330736 (indices of nonzero terms). %K A330735 nonn %O A330735 1,21 %A A330735 _Antti Karttunen_, Jan 10 2020