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 A379915 #13 Mar 31 2025 22:59:02 %S A379915 3,5,9,11,11,15,19,17,23,21,29,31,27,35,29,35,35,43,47,39,41,53,45,59, %T A379915 55,59,51,65,57,59,71,79,65,83,79,89,69,83,89,71,95,91,77,107,81,109, %U A379915 107,103,87,119,95,115,131,125,99,119,101,139,105,143,107,137,131 %N A379915 a(n) is the deficiency of the odd squarefree semiprime A046388(n), divided by 2. %H A379915 Hugo Pfoertner, <a href="/A379915/b379915.txt">Table of n, a(n) for n = 1..10000</a> %F A379915 a(n) = (2*A046388(n) - sigma(A046388(n)))/2, where sigma is A000203. %F A379915 a(n) = A033879(A046388(n))/2. %o A379915 (PARI) \\ uses function a379915_17 from A379917 %o A379915 a379915_17(300,2) %Y A379915 Cf. A000203, A033879, A046388, A379916, A379917. %K A379915 nonn %O A379915 1,1 %A A379915 _Hugo Pfoertner_, Jan 06 2025