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 A280703 #8 Mar 09 2017 09:58:19
%S A280703 1,1,1,1,1,1,1,9,1,7,1,15,1,11,1,9,1,25,1,21,1,13,1,45,1,17,25,11,1,
%T A280703 35,1,81,13,19,1,15,1,23,17,21,1,55,1,39,35,29,1,135,1,1,19,1,1,125,1,
%U A280703 9,23,31,1,105,1,37,55,27,1,1,1,57,29,77,1,225,1,41,49,23,1,85,1,189,125,43,1,165,1,47,31,39,1,175,1,87,37
%N A280703 a(n) = A003961(n) / A280702(n) = A003961(n) / gcd(A003961(n),A250469(n)).
%C A280703 If there are no such n that A250469(n) = k*A003961(n) for some integer k > 1, then A280693 gives the positions of ones in this sequence. Cf. also comment in A280704.
%H A280703 Antti Karttunen, <a href="/A280703/b280703.txt">Table of n, a(n) for n = 1..13330</a>
%F A280703 a(n) = A003961(n) / A280702(n) = A003961(n) / gcd(A003961(n),A250469(n)).
%t A280703 f[n_] := f[n] = Which[n == 1, 1, PrimeQ@ n, NextPrime@ n, True, Times @@ Replace[FactorInteger[n], {p_, e_} :> f[p]^e, 1]]; g[n_] := If[n == 1, 0, PrimePi@ FactorInteger[n][[1, 1]]]; Function[s, MapIndexed[ Function[p, p/GCD[Lookup[s, g@ First@ #2 + 1][[#1]] - Boole[First@ #2 == 1], p]]@ f@ First@ #2 &, #] &@ Map[Position[Lookup[s, g@ #], #][[1, 1]] &, Range@ 120]]@ PositionIndex@ Array[g, 10^4] (* _Michael De Vlieger_, Mar 08 2017, Version 10 *)
%o A280703 (Scheme) (define (A280703 n) (/ (A003961 n) (A280702 n)))
%Y A280703 Cf. A003961, A250469, A280702, A280704, A280693.
%K A280703 nonn
%O A280703 1,8
%A A280703 _Antti Karttunen_, Mar 08 2017