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 A130739 #20 Mar 24 2018 05:57:55
%S A130739 0,5,17,41,160,501,1720,6081,22548,80189,289176,1070091,3908641,
%T A130739 14584641,54056763,202288087,761593692,2867816043,10862883985,
%U A130739 41162256126,156592635694,596946687124,2280311678414,8729068693022
%N A130739 Sum of primes < 2^n.
%H A130739 Kim Walisch, <a href="/A130739/b130739.txt">Table of n, a(n) for n = 1..80</a> (terms n=1..42 from Cino Hilliard)
%H A130739 Kim Walisch, <a href="https://github.com/kimwalisch/primesum">primesum program</a>.
%F A130739 a(n) = Sum_{i=2..2^n-1} A061397(i).
%e A130739 a(3) is 17 because the sum of primes less than 2^3 is 2+3+5+7=17.
%t A130739 Table[Sum[Prime[i], {i, PrimePi[2^n-1]}], {n, 1, 10}]
%o A130739 (PARI) a(n) = {s = 0; forprime(p=2, 2^n-1, s +=p); return (s);} \\ _Michel Marcus_, Jul 17 2013
%Y A130739 Cf. A046731, A099824.
%K A130739 nonn
%O A130739 1,2
%A A130739 _Graeme McRae_, Jul 06 2007