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.

A375960 Numbers whose product of proper divisors is a cube.

This page as a plain text file.
%I A375960 #16 Sep 06 2024 17:28:02
%S A375960 1,2,3,5,7,8,11,13,16,17,19,23,24,27,29,30,31,37,40,41,42,43,47,53,54,
%T A375960 56,59,61,64,66,67,70,71,73,78,79,81,83,88,89,97,101,102,103,104,105,
%U A375960 107,109,110,113,114,125,127,128,130,131,135,136,137,138,139,149
%N A375960 Numbers whose product of proper divisors is a cube.
%C A375960 Wells erroneously writes that the smallest number on this list should be 24.
%C A375960 All the primes are in this list since they have the only proper divisor 1 which is trivially a cube.
%D A375960 David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, Revised edition 1987. See p. 101.
%H A375960 Stefano Spezia, <a href="/A375960/b375960.txt">Table of n, a(n) for n = 1..10000</a>
%e A375960 16 is a term since 1*2*4*8 = 64 = 4^3.
%t A375960 Select[Range[150],IntegerQ[Product[Part[Divisors[#],i],{i,DivisorSigma[0,#]-1}]^(1/3)] &]
%o A375960 (PARI) isok(k) = my(d=divisors(k)); ispower(vecprod(Vec(d, #d-1)), 3); \\ _Michel Marcus_, Sep 04 2024
%Y A375960 Cf. A000040 (subsequence), A000578, A007956, A027751, A032741.
%Y A375960 Complement of A375962.
%K A375960 nonn,easy
%O A375960 1,2
%A A375960 _Stefano Spezia_, Sep 04 2024