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 A102655 #13 Mar 29 2015 16:24:27
%S A102655 9,12,15,18,22,30,38,42,46,55,60,68,81,87,102,105,108,114,120,127,139,
%T A102655 144,149,155,165,175,181,186,195,200,215,228,232,241,247,253,260,265,
%U A102655 270,278,291,306,312,318,333,341,352,357,363,381,387,399,420,426,431
%N A102655 Numbers that are the arithmetic mean of four successive primes.
%F A102655 4*n = A000040(i) + A000040(i+1) + A000040(i+2) + A000040(i+3) for some i>=1.
%e A102655 a(1) = 9 because (5+7+11+13)/4=9;
%e A102655 a(2) = 12 because (7+11+13+17)/4=12;
%e A102655 a(3) = 15 because (11+13+17+19)/4=15.
%t A102655 Select[ Table[ Sum[ Prime[i], {i, n, n + 3}]/4, {n, 83}], IntegerQ[ # ] &] (* _Robert G. Wilson v_, Feb 04 2005 *)
%t A102655 Select[MovingAverage[Prime[Range[500]],4],IntegerQ] (* _Harvey P. Dale_, Aug 10 2012 *)
%Y A102655 Cf. A034963.
%K A102655 easy,nonn
%O A102655 1,1
%A A102655 _Giovanni Teofilatto_, Feb 02 2005
%E A102655 Edited by _Robert G. Wilson v_ and _W. Neville Holmes_, Feb 04 2005