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 A275390 #30 Mar 07 2018 14:19:00 %S A275390 1,2,3,6,7,15,23,39,42,43,115,223,231,239,474,719,1367,1403,1406,1407, %T A275390 1410,1411,1419,1646,1659,1662,1663,3423,8810,8818,8819,8822,8823, %U A275390 8915,9239,9242 %N A275390 Numbers n for which |n/zeta(2) - Q(n)| sets a new record, where Q(x) is the number of squarefree numbers up to x. %C A275390 Assuming the Riemann hypothesis, Vaidya proved that Q(n) = 6*n/Pi^2 + O(n^k) for any k > 2/5. %H A275390 Charles R Greathouse IV, <a href="/A275390/b275390.txt">Table of n, a(n) for n = 1..1000</a> %H A275390 A. M. Vaidya, <a href="http://www.new1.dli.ernet.in/data1/upload/insa/INSA_1/20005abb_196.pdf">On the order of the error function of the square free numbers</a>, Proc. Nat. Inst. Sci. India Part A 32 (1966), pp. 196-201. %o A275390 (PARI) ct=r=0; for(n=1,1e4, if(issquarefree(n),ct++); t=abs(n/zeta(2)-ct); if(t>r,r=t; print1(n", "))) %Y A275390 Cf. A005117, A013928. %K A275390 nonn %O A275390 1,2 %A A275390 _Charles R Greathouse IV_, Aug 07 2016