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 A066819 #9 Apr 29 2018 09:30:55 %S A066819 2,5,10,21,44,73,114,167,250,339,452,583,756,935,1126,1359,1598,1849, %T A066819 2130,2423,2782,3201,3632,4075,4566,5075,5668,6309,6962,7621,8304, %U A066819 9023,9766,10527,11336,12247,13200,14213,15232,16263,17312,18415,19638,20867 %N A066819 Sum of the first n Sophie Germain primes. %H A066819 Nathaniel Johnston, <a href="/A066819/b066819.txt">Table of n, a(n) for n = 1..10000</a> %t A066819 Accumulate[Select[Prime[Range[250]],PrimeQ[2#+1]&]] (* _Harvey P. Dale_, Apr 29 2018 *) %Y A066819 Cf. A005384. %K A066819 nonn %O A066819 1,1 %A A066819 _Joseph L. Pe_, Jan 19 2002 %E A066819 Extended beyond a(24) after confirming a(24). _Jonathan Vos Post_, Jan 23 2010 %E A066819 a(23) corrected by _Nathaniel Johnston_, Apr 29 2011