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 A037230 #30 May 15 2017 08:11:01 %S A037230 6,12,18,24,30,42,60 %N A037230 Numbers n such that phi(n) < pi(n). %C A037230 According to a note in Wacław Sierpiński's book "O stu prostych, ale trudnych zagadnieniach arytmetyki", a 1951 paper of L. Moser proves that 60 is the last term in the sequence. - _Arkadiusz Wesolowski_, Dec 22 2011 [A rough translation of the title of this book is "A hundred elementary but tough problems in arithmetic." No English translation appears to exist, but there are several later books by Sierpiński with similar titles that have been translated. I don't know if they give the Moser reference. - _N. J. A. Sloane_, Dec 26 2011] %C A037230 Leo Moser proved in 1951 that these are the only terms. - _Amiram Eldar_, May 15 2017 %H A037230 Leo Moser, <a href="http://www.pme-math.org/journal/issues/PMEJ.Vol.1.No.5.pdf">On the equation ϕ(n) = π(n)</a>, Pi Mu Epsilon Journal. Vol. 1, No. 5 (1951), pp. 177-180. %t A037230 Select[Range[60], EulerPhi[#] < PrimePi[#] &] (* _Arkadiusz Wesolowski_, Dec 22 2011 *) %Y A037230 Cf. A037171. %K A037230 nonn,fini,full %O A037230 1,1 %A A037230 _David W. Wilson_ %E A037230 Offset corrected by _Arkadiusz Wesolowski_, Dec 22 2011