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%I #26 Nov 27 2021 16:34:31
%S 40,67,94,112,121,148,157,175,187,202,220,229,247,256,262,283,292,310,
%T 312,337,346,364,367,382,391,409,412,418,427,437,445,472,487,499,514,
%U 517,526,535,544,553,562,577,580,598,607,612,634,637,643,652
%N Numbers k such that bigomega(2*k + 1) >= 4.
%C Numbers of the form k + A336263(m) + 2*k*A336263(m) where k and m are positive integers. If a term d in A336263 is not here, bigomega(2*d + 1) = 3.
%H Dumitru Damian, <a href="/A338373/b338373.txt">Table of n, a(n) for n = 1..30000</a>
%e 13 is in A336263, therefore 1 + 13 + 2*13*1 = 40 is a term, and (40*2) + 1 = 81 is not the product of 3 prime numbers.
%t Select[Range[650], PrimeOmega[2*# + 1] >= 4 &] (* _Amiram Eldar_, Oct 24 2020 *)
%o (PARI) isok(k) = bigomega(2*k+1) >= 4; \\ _Michel Marcus_, Oct 24 2020
%Y Cf. A001222, A336263, A159919.
%K nonn
%O 1,1
%A _Davide Rotondo_, Oct 23 2020
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