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 A329239 #32 Mar 15 2020 03:22:51 %S A329239 1,7,102,110,120,142,159,184,187,381,588,684,690,714,770,796,840,931, %T A329239 994,1034,1054,1065,1113,1128,1173,1240,1265,1288,1293,1309,1528,1633, %U A329239 1643,2619,2667,3638,3937,4280,4505,4664,4788,4830,4855,5176,5572,5671,5730 %N A329239 Numbers k such that the sum of unitary divisors of k is a cube. %H A329239 Amiram Eldar, <a href="/A329239/b329239.txt">Table of n, a(n) for n = 1..10000</a> %e A329239 7 is a term since usigma(7) = 8 = 2^3, where usigma is A034448. %e A329239 102 is a term since usigma(102) = 216 = 6^3. %t A329239 usigma[1] = 1; usigma[n_] := Times @@ (1 + Power @@@ FactorInteger[n]); Select[Range[10000], IntegerQ @ Surd[usigma [#], 3] &] %o A329239 (PARI) isok(m) = ispower(sumdiv(m, d, if(gcd(d, m/d)==1, d)), 3); \\ _Michel Marcus_, Mar 15 2020 %Y A329239 The unitary version of A020477. %Y A329239 Cf. A000578, A034448, A063937, A333258. %K A329239 nonn %O A329239 1,2 %A A329239 _Amiram Eldar_, Mar 13 2020