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 A277186 #35 Nov 24 2016 09:49:38
%S A277186 5,10,17,26,31,67,83,83,119,139,161,228,281,281,341,408,474,553,546,
%T A277186 635,635,780,824,1092,954,1008,1008,1139,1197,1336,1621,1687,1650,
%U A277186 1823,1854,1854,2238,2634,2507,2587,2450,2673,3223,3223,3403,3403,3591,4054,4054,4331,4535,4535,4828,4444,4666
%N A277186 Sum of primes within 2n-wide closed interval centered upon prime(n).
%C A277186 a(n) is the sum of primes within the closed interval [prime(n)-n, prime(n)+n], where prime(n) is the n-th prime.
%e A277186 a(3) = 2 + 3 + 5 + 7 = 17; starting at prime(3) = 5, subtract 3 and add 3 to obtain the interval 2 through 8, and then add up the primes within that interval, inclusive of the endpoints of the interval.
%t A277186 Table[Total@ Select[Range[Prime@ n - n, Prime@ n + n], PrimeQ], {n, 55}] (* _Michael De Vlieger_, Oct 04 2016 *)
%o A277186 (PARI) a(n) = sum(k=prime(n)-n, prime(n)+n, isprime(k)*k); \\ _Michel Marcus_, Nov 01 2016
%Y A277186 Cf. A000040, A014688, A014689, A061397.
%K A277186 nonn,easy
%O A277186 1,1
%A A277186 _Walter Carlini_, Oct 04 2016
%E A277186 More terms from _Michael De Vlieger_, Oct 04 2016