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 A286228 #14 Aug 03 2019 07:57:56 %S A286228 1,4,9,12,18,20,25,28,44,45,49,50,52,63,68,75,76,92,98,99,116,117,121, %T A286228 124,147,148,153,164,169,171,172,175,188,207,212,236,242,244,245,261, %U A286228 268,275,279,284,289,292,316,325,332,333,338,356,361,363,369,387,388,404,412,423,425,428 %N A286228 Numbers n such that d(n) = 2^omega(n) + omega(n) where d = A000005 and omega = A001221. %H A286228 Amiram Eldar, <a href="/A286228/b286228.txt">Table of n, a(n) for n = 1..10000</a> %e A286228 1 is in this sequence because d(1) = 1 is equal to 2^omega(1) + omega(1) = 2^0 + 0 = 1. %t A286228 Select[Range@ 432, Function[f, DivisorSigma[0, #] == 2^f + f]@ PrimeNu@ # &] (* _Michael De Vlieger_, May 04 2017 *) %o A286228 (PARI) isok(n) = numdiv(n) == 2^omega(n) + omega(n); \\ _Michel Marcus_, May 07 2017 %Y A286228 Supersequence of A001248 and of A054753. %Y A286228 Cf. A006127. %K A286228 nonn %O A286228 1,2 %A A286228 _Juri-Stepan Gerasimov_, May 04 2017