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.

A067341 Number of prime factors divided by the number of distinct prime factors is an integer and n is neither squarefree, nor power of prime.

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%I A067341 #15 Jan 10 2025 10:08:16
%S A067341 24,36,40,54,56,88,96,100,104,135,136,144,152,160,184,189,196,216,224,
%T A067341 225,232,240,248,250,296,297,324,328,336,344,351,352,360,375,376,384,
%U A067341 400,416,424,441,459,472,484,486,488,504,513,528,536,540,544,560,568
%N A067341 Number of prime factors divided by the number of distinct prime factors is an integer and n is neither squarefree, nor power of prime.
%H A067341 Amiram Eldar, <a href="/A067341/b067341.txt">Table of n, a(n) for n = 1..10000</a>
%F A067341 A001222(n)/A001221(n) is an integer, A001222(n)>A001221(n)>1.
%t A067341 ff[x_] := Flatten[FactorInteger[x]] f1[x_] := Length[FactorInteger[x]] f2[x_] := Apply[Plus, Table[Part[ff[x], 2*w], {w, 1, f1[x]}]] Do[s=f2[n]/f1[n]; If[IntegerQ[s]&&Greater[s, 1]&&Greater[f1[n], 1], Print[n]], {n, 2, 10000}]
%o A067341 (PARI) is(n)=my(f=factor(n)[, 2]); #f>1 && vecsum(f)%#f==0 && vecmax(f)>1 \\ _Charles R Greathouse IV_, Oct 15 2015
%Y A067341 Cf. A001221, A001222, A067340.
%K A067341 nonn
%O A067341 1,1
%A A067341 _Labos Elemer_, Jan 16 2002