cp's OEIS Frontend

A353388 Numbers k such that 2*k^2 + 29 is neither a prime nor a semiprime.

%I A353388 #16 Aug 02 2023 08:06:02
%S A353388 185,187,232,247,261,309,311,370,371,373,435,442,464,479,501,516,520,
%T A353388 553,557,561,590,614,619,620,621,627,638,667,701,702,705,708,714,738,
%U A353388 755,769,796,797,802,812,836,849,853,856,869,874,890,896,899,903,906,915,943,957,960,964,973,990
%N A353388 Numbers k such that 2*k^2 + 29 is neither a prime nor a semiprime.
%C A353388 If k is a term, then so is k + j*(2*k^2+29) for all natural numbers j. - _Robert Israel_, Jul 23 2023
%H A353388 Robert Israel, <a href="/A353388/b353388.txt">Table of n, a(n) for n = 1..10000</a>
%p A353388 select(k -> numtheory:-bigomega(2*k^2+29) > 2, [$1..1000]); # _Robert Israel_, Jul 23 2023
%t A353388 Select[Range[1000], PrimeOmega[2*#^2 + 29] >= 3 &] (* _Amiram Eldar_, Apr 17 2022 *)
%o A353388 (PARI) for(k=0,1000,if(bigomega(2*k^2+29) >= 3,print1(k,", ")))
%o A353388 (Python)
%o A353388 from sympy import primeomega
%o A353388 def ok(n): return primeomega(2*n**2 + 29) >= 3
%o A353388 print([k for k in range(1000) if ok(k)]) # _Michael S. Branicky_, Apr 16 2022
%Y A353388 Cf. A007642, A353004.
%K A353388 nonn
%O A353388 1,1
%A A353388 _Hugo Pfoertner_, Apr 16 2022