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 A307328 #17 May 13 2024 05:21:16
%S A307328 2,3,7,8,15,17,25,31,41,48,69,73,91,97,106,107,123,125,138,167,172,
%T A307328 177,181,193,194,241,242,246,267,280,286,287,297,306,312,322,323,338,
%U A307328 340,343,353,354,382,388,393,398,403,411,412,415,416,433,444,448,460
%N A307328 Indices of prime Ulam numbers: numbers k such that A002858(k) is prime.
%H A307328 Amiram Eldar, <a href="/A307328/b307328.txt">Table of n, a(n) for n = 1..10000</a>
%F A307328 A002858(a(n)) = A068820(n).
%t A307328 ulams = {1, 2}; Do[AppendTo[ulams, n = Last[ulams]; While[n++; Length[ DeleteCases[Intersection[ulams, n - ulams], n/2, 1, 1]] != 2]; n], {100}]; Flatten[Position[ulams, _?(PrimeQ[#] &)]] (* after _Jean-François Alcover_ at A002858 *)
%Y A307328 Cf. A002858, A068820.
%K A307328 nonn
%O A307328 1,1
%A A307328 _Amiram Eldar_, Apr 02 2019