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 A328498 #30 Dec 01 2019 17:07:50
%S A328498 1,8,3,5,0,0,3,8
%N A328498 Decimal expansion of Sum_{(p, q) runs through the twin primes} ((p mod 4) - 2) * (1/p + 1/q).
%C A328498 Because Viggo Brun's constant is 1.90216058... it is easy to find these 2 new constants:
%C A328498 (1/3 + 1/5) + (1/11 + 1/13) + (1/59 + 1/61) + (1/71 + 1/73) + ... = 1.04283048...
%C A328498 (1/5 + 1/7) + (1/17 + 1/19) + (1/29 + 1/31) + (1/41 + 1/43) + ... = 0.85933010...
%e A328498 (1/3 + 1/5) - (1/5 + 1/7) + (1/11 + 1/13) - (1/17 + 1/19) - (1/29 + 1/31) + ... = 0.183500386... +- 0.000000002
%o A328498 (PARI) my(p = 3, s = 0.0); forprime(n = 5, 10^16, if(n-p == 2, if(p%4 == 3, s+= 1/p + 1/n, s+= -1/p - 1/n)); p = n); s
%Y A328498 Cf. A001359, A006512, A065421.
%K A328498 nonn,cons,more
%O A328498 0,2
%A A328498 _Dimitris Valianatos_, Oct 17 2019