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 A214442 #9 Jul 23 2012 14:55:09
%S A214442 3,18,3318,39193162,943016093,390502539,3
%N A214442 Arithmetic mean of next a(n) > 1 successive odd primes is prime.
%C A214442 Two or more primes in the arithmetic mean.
%C A214442 Corresponding prime arithmetic means: 5, 43, 14639, 369687067, 11370090223, 27055575571, 31756143437
%e A214442 (3+5+7)/3 is prime, so a(1)=3; next (11+13+...+73+79)/18=43 is prime, so a(2)=18.
%t A214442 n = 1; Table[n++; s = Prime[n]; num = 1; While[num == 1 || ! PrimeQ[s/num], n++; num++; s = s + Prime[n]]; num, {3}] (* _T. D. Noe_, Jul 23 2012 *)
%Y A214442 Cf. A000040, A073684.
%K A214442 nonn,more
%O A214442 1,1
%A A214442 _Alex Ratushnyak_, Jul 18 2012