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

185, 187, 232, 247, 261, 309, 311, 370, 371, 373, 435, 442, 464, 479, 501, 516, 520, 553, 557, 561, 590, 614, 619, 620, 621, 627, 638, 667, 701, 702, 705, 708, 714, 738, 755, 769, 796, 797, 802, 812, 836, 849, 853, 856, 869, 874, 890, 896, 899, 903, 906, 915, 943, 957, 960, 964, 973, 990

Offset: 1

Author

Hugo Pfoertner, Apr 16 2022

Keywords

• nonn

Comments

If k is a term, then so is k + j*(2*k^2+29) for all natural numbers j. - Robert Israel, Jul 23 2023

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007642, A353004.

Programs

Maple

select(k -> numtheory:-bigomega(2*k^2+29) > 2, [$1..1000]); # Robert Israel, Jul 23 2023

Mathematica

Select[Range[1000], PrimeOmega[2*#^2 + 29] >= 3 &] (* Amiram Eldar, Apr 17 2022 *)

PARI

for(k=0,1000,if(bigomega(2*k^2+29) >= 3,print1(k,", ")))

Python

from sympy import primeomega
def ok(n): return primeomega(2*n**2 + 29) >= 3
print([k for k in range(1000) if ok(k)]) # Michael S. Branicky, Apr 16 2022