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 A050513 #7 Mar 01 2016 09:05:54
%S A050513 2,-7,20,-53,136,-341,836,-2005,4712,-10881,24770,-55763,124464,
%T A050513 -275933,608282,-1334119,2911870,-6325091,13674120,-29425307,63042232,
%U A050513 -134517425,285984130,-606056545,1280778342,-2700105565,5680099084,-11925792491
%N A050513 a(n) = (-1)^n * Sum_{i=0..n} binomial(n+1,i+1)*prime(i+1).
%t A050513 Table[(-1)^(n-1)*Sum[Binomial[n, k]*Prime[k], {k, 1, n}], {n, 1, 20}] (* _Vaclav Kotesovec_, Mar 01 2016 *)
%Y A050513 Cf. A030015.
%K A050513 sign
%O A050513 0,1
%A A050513 _N. J. A. Sloane_, Dec 28 1999