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 A105402 #16 Jun 02 2020 07:55:01 %S A105402 1,6,28,30,42,66,84,102,120,138,186,210,270,282,318,330,364,420,426, %T A105402 462,496,510,546,570,642,672,690,714,762,840,868,870,924,930,966,1080, %U A105402 1092,1122,1146,1302,1320,1410,1428,1488,1518,1590,1638,1722,1770,1782,1890 %N A105402 Positive integers k such that the prime factors of sigma(k) are a subset of the prime factors of k. %C A105402 Also numbers k such that k^k/sigma(k) is integral. - _Vicente Izquierdo Gomez_, Jan 04 2013. %C A105402 Pollack and Pomerance call these numbers "prime-deficient numbers". - _Amiram Eldar_, Jun 02 2020 %H A105402 Amiram Eldar, <a href="/A105402/b105402.txt">Table of n, a(n) for n = 1..10000</a> %H A105402 Paul Pollack and Carl Pomerance, <a href="http://www.emis.de/journals/INTEGERS/papers/a14self/a14self.Abstract.html">Prime-Perfect Numbers</a>, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 12a, Paper A14, 2012. %e A105402 102 is a term since 102 = 2*3*17 and sigma(102) = 2^3*3^3. %p A105402 A:=select(proc(z) numtheory[factorset](sigma(z)) subset numtheory[factorset](z) end,[$1..100000]); has 716 members. %t A105402 Select[Range[2000],IntegerQ[#^#/DivisorSigma[1,#]] &] (* _Vicente Izquierdo Gomez_, Jan 04 2013 *) %Y A105402 Cf. A000203, A027598, A058063, A054027, A014567, A023194, A175200. %K A105402 easy,nonn %O A105402 1,2 %A A105402 _Walter Kehowski_, May 01 2005 %E A105402 Extended by _R. J. Mathar_, Dec 08 2008