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 A385959 #40 Aug 06 2025 19:59:59
%S A385959 1,2,3,4,6,7,14,15,16,18,19,38,57,76,114,115,120,121,132,135,136,138,
%T A385959 139,278,279,310,312,314,471,628,942,1099,2198,2199,2932,4398,5131,
%U A385959 10262,10995,10996,16494,19243,38486,41235,41236,41358,41471,41838,41841,46490,55788,55789,111578,167367,168554,252831,252832,252864
%N A385959 a(0) = 1; a(n) = a(n-1)*(b(n)+1)/(b(n)-1), where b(n) = A385958(n) is the largest prime p such that a(n) is an integer.
%C A385959 a(0) = 1; a(n) is the smallest k such that (k + a(n-1))/(k - a(n-1)) is a prime (A385958).
%C A385959 Note that a(n-1)+1 <= a(n) <= 2*a(n-1).
%H A385959 Martin Fuller, <a href="/A385959/b385959.txt">Table of n, a(n) for n = 0..3460</a>
%F A385959 a(n) = Product_{k=1..n} (b(k)+1)/(b(k)-1), where b(n) = A385958(n).
%F A385959 a(n) = (1+t(n))/(1-t(n)) with t(n) = tanh(Sum_{k=1..n} arctanh(1/b(k))).
%Y A385959 Cf. A385958.
%K A385959 nonn,look
%O A385959 0,2
%A A385959 _Thomas Ordowski_, Jul 13 2025
%E A385959 More terms from Morné Louw and _Martin Fuller_, Jul 15 2025