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 A263076 #15 Oct 23 2015 13:47:34
%S A263076 2,1810,2458,240926,317602,757730,771610,23993994,58292586,172616042
%N A263076 Numbers n such that the fractional part of the sum of the first n primes (A007504) divided by n equals 1/2.
%C A263076 Inspired by A075465.
%C A263076 No other terms < 10^9.
%C A263076 All terms are even. - _Charles R Greathouse IV_, Oct 09 2015
%e A263076 a(1) = 2 since A007504(2) = 5 and 5/2 has a remainder of half of 2 which is 1.
%e A263076 a(2) = 1810 because A007504(1810) = 13150555 and 13150555/1810 = 14531/2.
%t A263076 p = 2; k = s = 0; lst = {}; While[k < 100000001, s = s + p; If[ 2Mod[s, ++k] == k, AppendTo[lst, k]; Print[k]]; p = NextPrime@ p; k++]
%o A263076 (PARI) n=s=0; forprime(p=2,, s+=p; n++; if(n%2==0 && s%n == n/2, print1(n", "))) \\ _Charles R Greathouse IV_, Oct 09 2015
%Y A263076 Cf. A007504, A045345, A075465.
%K A263076 nonn,more,hard
%O A263076 1,1
%A A263076 _Robert G. Wilson v_, Oct 09 2015