A337837 Numbers k such that Omega(3^k - 2) = Omega(3^k + 2) where Omega is A001222.

2, 4, 12, 18, 20, 28, 30, 31, 34, 35, 38, 44, 45, 49, 50, 58, 60, 75, 79, 97, 100, 103, 111, 113, 118, 120, 135, 141, 153, 154, 156, 166, 168, 171, 178, 181, 204, 219, 220, 239, 245, 247, 254, 260, 267, 269, 280, 286, 298, 307, 313

Offset: 1

Author

Zak Seidov, Sep 25 2020

Keywords

• nonn

Comments

The corresponding values of Omega: 1, 1, 2, 3, 2, 2, 3, 3, 3, 3, 4, 2, 3, 3, 3, 3, 2, 6, 5, 4, 3, 4, 4, 4, 2, 4, 3, 3, 7, 4, 2, 4, 4, 4, 4, 5, 5, 5, 3, 5, 5, 6, 5, 6, 4, 5, 4, 5, 7, 6, 8.

Examples

			2 is a term since Omega(3^2 - 2) = Omega(7) = 1, and Omega(3^2 + 2) = Omega(11) = 1.
		

Crossrefs

Cf. A001222, A014224, A051783, A058481, A168607.

Programs

Mathematica

Select[Range[200],PrimeOmega[3^#-2] == PrimeOmega[3^#+2]&]

PARI

for (k = 1, 200, if ((m = bigomega (3^k - 2)) == bigomega (3^k + 2), print (k ", " m ", ")))

Extensions

a(36)-a(51) from Amiram Eldar, Sep 25 2020