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 A162196 #6 Apr 30 2019 00:24:20 %S A162196 0,1,3,4,2,5,11,7,6,11,16,17,8,11,29,4,13,10,23,35,26,12,17,10,47,19, %T A162196 14,43,47,35,28,23,67,6,38,18,41,59,14,57,20,29,97,31,36,57,16,71,53, %U A162196 24,67,112,37,44,59,16,83,97,36,41,129,20,43,30 %N A162196 Sum of proper divisors minus the number of proper divisors of nonprime number A018252(n). %C A162196 Also, zero together with the positive integers of A152770. %C A162196 Note that the k-th positive integer of this sequence is equal to the sum of proper divisors minus the number of proper divisors of the composite number A002808(k). %F A162196 a(n) = A152770(A018252(n)). %F A162196 a(n) = A001065(A018252(n)) - A032741(A018252(n)). %p A162196 A162196 := proc(n) %p A162196 A152770(A018252(n)) ; %p A162196 end proc: # _R. J. Mathar_, Sep 28 2011 %Y A162196 Cf. A001065, A018252, A002808, A032741, A152770, A152988, A152989, A152990, A162194, A162195. %K A162196 easy,nonn %O A162196 1,3 %A A162196 _Omar E. Pol_, Jul 04 2009