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 A172239 #2 Mar 30 2012 18:40:50
%S A172239 2,5,12,43,254,2565,200560492696,
%T A172239 1719620105458406433483340568317543019584575635895742560438771105058321655238562613083979651479555788009994557822024565226932906295208262756822476224186807
%N A172239 Partial sums of primorial primes A018239.
%C A172239 The subsequence of primes in this sequence begin: a(1) = 2, a(2) = 5, a(4) = 43. The subsubsequence of primorial prime partial sums of primorial primes begins 2, 5. Will someone extend these subsequences?
%F A172239 a(n) = SUM[i=1..n] A018239(i) = SUM[i=1..n] {p in A006862 and p prime} = SUM[i=1..n] (1 + Product[j=1..i] A000040(i)).
%e A172239 a(4) = 2 + 3 + 7 + 31 = 43, which is prime, but not primorial prime.
%Y A172239 Cf. A000040, A002110, A018239.
%K A172239 nonn
%O A172239 1,1
%A A172239 _Jonathan Vos Post_, Jan 29 2010