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 A063849 #15 Jun 25 2018 03:42:33
%S A063849 8,13,21,24,25,26,37,44,49,50,54,57,62,63,74,75,80,90,115,116,119,120,
%T A063849 123,134,146,157,160,175,177,185,187,206,207,209,224,234,248,253,259,
%U A063849 260,265,274,278,287,294,295,296,304,314,321,323,324,329,332,338,340
%N A063849 Numbers k such that mu(k) + mu(k+1) + mu(k+2) = 1.
%H A063849 Harry J. Smith, <a href="/A063849/b063849.txt">Table of n, a(n) for n = 1..1000</a>
%o A063849 (PARI) m(n)=moebius(n)+moebius(n+1)+moebius(n+2);
%o A063849 j=[]; for(n=1,1000, if(m(n)==1,j=concat(j,n))); j
%o A063849 (PARI) M(n) = moebius(n) + moebius(n + 1) + moebius(n + 2)
%o A063849 { n=0; for (m=1, 10^9, if(M(m)==1, write("b063849.txt", n++, " ", m); if (n==1000, break)) ) } \\ _Harry J. Smith_, Sep 01 2009
%Y A063849 Cf. A063838.
%K A063849 easy,nonn
%O A063849 1,1
%A A063849 _Jason Earls_, Aug 26 2001