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