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 A179179 #9 Apr 23 2017 01:01:59
%S A179179 1,0,1,1,3,0,5,3,5,2,9,2,11,4,6,7,15,4,17,6,10,8,21,6,19,10,17,10,27,
%T A179179 5,29,15,18,14,22,10,35,16,22,14,39,9,41,18,22,20,45,14,41,18,30,22,
%U A179179 51,16,38,22,34,26,57,13,59,28,34,31,46,17,65,30,42,21,69,22,71,34,38,34,58
%N A179179 a(n) = phi(n) - omega(n) = A000010(n) - A001221(n).
%C A179179 a(n) is the number of positive integers which are coprime to n minus the number of distinct primes dividing n.
%H A179179 Alois P. Heinz, <a href="/A179179/b179179.txt">Table of n, a(n) for n = 1..10000</a>
%H A179179 Peter Luschny, Blog on OEIS, <a href="http://oeis.org/wiki/User:Peter_Luschny/EulerTotient"> Euler's totient function</a>
%F A179179 a(n) = phi(n) - omega(n), by definition.
%e A179179 a(7) = phi(7) - omega(7) = card({1,2,3,4,5,6}) - card({7}) = 6 - 1 = 5
%p A179179 with(numtheory): a := n -> phi(n) - nops(factorset(n));
%t A179179 Table[EulerPhi[n] - PrimeNu[n], {n,1,50}] (* _G. C. Greubel_, Apr 23 2017 *)
%Y A179179 Cf. A000010, A001221, A057859.
%K A179179 nonn
%O A179179 1,5
%A A179179 _Peter Luschny_, Jun 30 2010