cp's OEIS Frontend

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.

A357687 Nonsquarefree numbers k such that A048250(k) > 2*k.

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%I A357687 #6 Oct 09 2022 12:05:32
%S A357687 401120980260,14841476269620,16445960190660,17248202151180,
%T A357687 18852686072220,608500527054420,638183479593660,697549384672140,
%U A357687 707176288198380,772960128961020,810665501105460,26165522663340060,28599524771557740,29994623540902020,33237285545323860,1229779565176982820
%N A357687 Nonsquarefree numbers k such that A048250(k) > 2*k.
%C A357687 The squarefree numbers k such that A048250(k) > 2*k are the squarefree abundant numbers (A087248).
%C A357687 The least odd term is 3*prime(553)#/2 = 3.735...*10^1709.
%t A357687 q[n_] := Module[{f = FactorInteger[n]}, AnyTrue[f[[;;, 2]], # > 1 &] && Times @@ (f[[;;, 1]]+1) > 2*n];
%o A357687 (PARI) is(n) = {my(f = factor(n)); if(n == 1 || vecmax(f[,2]) == 1, return(0)); prod(i=1, #f~, f[i,1]+1) > 2*n};
%Y A357687 Subsequence of A005101 and A013929.
%Y A357687 Cf. A005117, A048250, A087248, A357685, A357686.
%K A357687 nonn
%O A357687 1,1
%A A357687 _Amiram Eldar_, Oct 09 2022