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 A305702 #10 Jun 10 2018 14:44:59
%S A305702 1,1,1,2,6,12,20,10,84,840,72,630,1320,2772,1560,90090,42,240240,1904,
%T A305702 46410,95760,639540,5040,9699690,637560,14316120,92400,176125950,
%U A305702 308880,20078358300,475020,67690350,7447440,116925953760,110880,1002802450650,318240,122453100,906665760,165723680430
%N A305702 a(n) is the denominator of Sum_{primes p < n} 1/(n-p).
%C A305702 The first n >= 2 for which a(n) <> A130492(n-1) is 32.
%H A305702 Robert Israel, <a href="/A305702/b305702.txt">Table of n, a(n) for n = 1..3569</a>
%H A305702 Math Overflow, <a href="https://mathoverflow.net/questions/302351/sum-of-reciprocals-of-integers-minus-primes">Sum of reciprocals of integers minus primes</a>.
%e A305702 Sum_{primes p < 6} 1/(6-p) = 1/(6-2) + 1/(6-3) + 1/(6-5) = 19/12 so a(6) = 12.
%p A305702 N:= 100: # to get a(1)..a(N)
%p A305702 P:= select(isprime, [2,seq(i,i=3..N,2)]):
%p A305702 seq(denom(add(1/(n-p),p=select(`<`,P,n))), n=1..N);
%o A305702 (PARI) a(n) = my(p=select(x->isprime(x), [1..n-1])); denominator(sum(k=1, #p, 1/(n-p[k]))); \\ _Michel Marcus_, Jun 09 2018
%Y A305702 Cf. A130492, A305700.
%K A305702 nonn,frac
%O A305702 1,4
%A A305702 _Robert Israel_, Jun 08 2018