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.

A357685 Numbers k such that A293228(k) > k.

This page as a plain text file.
%I A357685 #10 Oct 12 2022 04:34:49
%S A357685 30,42,60,66,70,78,84,102,114,132,138,140,156,174,186,204,210,222,228,
%T A357685 246,258,276,282,318,330,348,354,366,372,390,402,420,426,438,444,462,
%U A357685 474,492,498,510,516,534,546,564,570,582,606,618,636,642,654,660,678,690
%N A357685 Numbers k such that A293228(k) > k.
%C A357685 The numbers of terms not exceeding 10^k, for k = 2, 3, ..., are 7, 79, 843, 8230, 83005, 826875, 8275895, 82790525, 827718858, 8276571394, ... . Apparently, the asymptotic density of this sequence exists and equals 0.0827... .
%H A357685 Amiram Eldar, <a href="/A357685/b357685.txt">Table of n, a(n) for n = 1..10000</a>
%e A357685 30 is a term since its aliquot squarefree divisors are {1, 2, 3, 5, 6, 10, 15} and their sum is 42 > 30.
%e A357685 60 is a term since its aliquot squarefree divisors are {1, 2, 3, 5, 6, 10, 15, 30} and their sum is 72 > 60.
%t A357685 s[n_] := Times @@ (1 + (f = FactorInteger[n])[[;; , 1]]) - If[AllTrue[f[[;;, 2]], # == 1 &], n, 0]; Select[Range[2, 1000], s[#] > # &]
%o A357685 (PARI) is(n) = {my(f = factor(n), s); s = prod(i=1, #f~, f[i,1]+1); if(n==1 || vecmax(f[,2]) == 1, s -= n); s > n};
%Y A357685 Cf. A005117, A293228.
%Y A357685 Disjoint union of A087248 and A357686.
%Y A357685 Subsequence of A005101.
%Y A357685 Similar sequences: A034683, A064597, A129575, A129656, A292982, A348274, A348604.
%K A357685 nonn
%O A357685 1,1
%A A357685 _Amiram Eldar_, Oct 09 2022