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 A357023 #32 Oct 16 2022 03:23:41 %S A357023 4,185,206,209,27681,3066905,3067135,3067795,3067985,348933197, %T A357023 348933239,348933251,348933257,348933269,44690978141,44690978162, %U A357023 44690978519,44690978561,44690978617,44690978869,44690978981,44690979457,44690979527,6553736049293 %N A357023 Semiprimes k such that k is congruent to 5 modulo k's index in the sequence of semiprimes. %C A357023 a(32) > 8040423200947. %H A357023 Lucas A. Brown, <a href="/A357023/b357023.txt">Table of n, a(n) for n = 1..31</a> %H A357023 Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/semiprimemods.py">semiprimemods.py</a>. %F A357023 a(n) = A001358(A106130(n)). %e A357023 The 1st semiprime is 4, which is congruent to 5 (mod 1), so 4 is in the sequence. %e A357023 The 2nd semiprime is 6, which is not congruent to 5 (mod 6), so 6 is not in the sequence. %e A357023 The 60th semiprime is 185, which is congruent to 5 (mod 60), so 185 is in the sequence. %Y A357023 Cf. A001358, A106130. %K A357023 nonn,hard %O A357023 1,1 %A A357023 _Lucas A. Brown_, Oct 14 2022