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 A175217 #6 Nov 12 2017 03:02:44
%S A175217 6,6,8,9,14,15,20,21,25,32,33,39,44,45,49,55,62,63,69,74,75,81,85,91,
%T A175217 99,104,105,110,111,115,129,133,140,141,152,153,159,165,169,175,182,
%U A175217 183,194,195,200,201,213,225,230,231,235,242,243,253,259,265,272,273,279
%N A175217 The second nonprimes after the primes.
%F A175217 a(n) = prime(n)+2 + A010051(prime(n)+1) + A010051(prime(n)+2) + A010051(prime(n)+3). [From _Reinhard Zumkeller_, Mar 29 2010]
%t A175217 b[n_] := Boole[PrimeQ[n]];
%t A175217 a[n_] := With[{p = Prime[n]}, p + 2 + b[p + 1] + b[p + 2] + b[p + 3]];
%t A175217 Array[a, 59] (* _Jean-François Alcover_, Nov 12 2017, after _Reinhard Zumkeller_ *)
%K A175217 nonn,easy
%O A175217 1,1
%A A175217 _Jaroslav Krizek_, Mar 06 2010
%E A175217 More terms from _Reinhard Zumkeller_, Mar 29 2010
%E A175217 Typos in data corrected by _Jean-François Alcover_, Nov 12 2017