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 A247234 #38 Jun 14 2025 23:49:30
%S A247234 2,4,7,20,8,17,39,134,45,206,149,49,66,321,88,98,637,382,259,284,820,
%T A247234 302,310,1102,1597,3763,1140,3432,741,532,4751,856,4855,3446,2130,
%U A247234 3256,3407,694,2250,4878,5588,13199,15211,9040,7426,11126,5931,11699,22463,26223,37546,37602,42795,32776
%N A247234 First occurrence of 2*n in A035096.
%H A247234 Robert G. Wilson v, <a href="/A247234/b247234.txt">Table of n, a(n) for n = 1..276</a>
%e A247234 a(1) = 2 since the first appearance of 2 occurs at A035096(2);
%e A247234 a(3) = 7 since the first appearance of 6 occurs at A035096(7).
%t A247234 f[n_] := Block[{p = Prime@ n}, q = 1 + 2p; While[ !PrimeQ@ q, q += 2p]; (q - 1)/p]; f[1] = 1; t = Table[0, {1000}]; k = 2; While[k < 10^5, a = f@ k /2; If[ t[[a]] == 0, t[[a]] = k; Print[{a, k}]]; k++]; t
%Y A247234 Cf. A035096.
%K A247234 nonn
%O A247234 1,1
%A A247234 _Robert G. Wilson v_, Dec 28 2014