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 A077149 #5 Dec 05 2013 19:55:49
%S A077149 3,7,13,13,31,16,57,25,37,27,133,31,183,39,49,49,307,46,381,55,71,63,
%T A077149 553,61,151,75,109,78,871,71,993,97,118,99,148,91,1407,111,142,107,
%U A077149 1723,101,1893,125,142,135,2257,121,393,135,188,149,2863,136,256,155
%N A077149 a(1) =3. For n>1, a(n) = smallest k such that there are n numbers m not relatively prime to n in range n < m < k.
%C A077149 a(p) = p^2 + p +1, a(2^m) = 3*2^m +1,a(p^m) = p^m + p^(m+1) +1, if p is a prime.
%e A077149 a(5) = 31 as there are 5 non-coprime numbers to 5 between 5 and 31, i.e. 10,15,20,25 and 30.
%o A077149 (PARI) print1("3,"):for(n=2,100,s=0:for(k=n+1,10^9,if(gcd(n,k)>1,s=s+1): if(s==n,s=k:break)):print1(s+1","))
%Y A077149 Cf. A077148.
%K A077149 nonn
%O A077149 1,1
%A A077149 _Amarnath Murthy_, Oct 30 2002
%E A077149 More terms from _Ralf Stephan_, Mar 25 2003