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 A173242 #12 Aug 28 2020 06:15:49
%S A173242 1,3,9,10,40,41,83,84,114,115,181,182,2912,2913,2919,2920,3430,3431,
%T A173242 4229,4230,4560,4561,4699,4700,7430,7431,7437,7438,8308,8309,22631,
%U A173242 22632,23142,23143,23149,23150,1942340,1942341,1942347,1942348,1955878
%N A173242 Partial sums of A027642.
%F A173242 a(n) = Sum_{i=0..n} A027642(i).
%o A173242 (PARI) a(n) = sum(k=0, n, denominator(bernfrac(k))); \\ _Michel Marcus_, Aug 28 2020
%Y A173242 Cf. A027642.
%K A173242 nonn
%O A173242 0,2
%A A173242 _Jonathan Vos Post_, Feb 13 2010
%E A173242 a(19) corrected by _Georg Fischer_, Aug 28 2020