A271909 Numbers k such that k and 3*k+1 have the same number of prime divisors (including multiplicities).

2, 15, 35, 38, 39, 55, 62, 63, 82, 86, 87, 91, 105, 106, 111, 114, 115, 118, 119, 134, 142, 147, 155, 159, 178, 187, 189, 194, 212, 218, 225, 226, 235, 238, 254, 258, 259, 267, 268, 275, 278, 282, 287, 295, 298, 299, 310, 314, 319, 326, 327, 334, 335, 338, 339, 343

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

Numbers k such that bigomega(k) = bigomega(3*k+1).

Maple

with(numtheory): A271909:=n->`if`(bigomega(n)=bigomega(3*n+1), n, NULL): seq(A271909(n), n=1..800); # Wesley Ivan Hurt, Apr 22 2016

Mathematica

Select[Range[350], PrimeOmega[#] == PrimeOmega[3 # + 1] &] (* Amiram Eldar, Apr 02 2020 *)

Crossrefs

Cf. A001222, A272229.

Sequence in context: A300765 A300635 A301357 * A346641 A075541 A075542

Adjacent sequences: A271906 A271907 A271908 * A271910 A271911 A271912

Keyword

nonn

Author

Benjamin Przybocki, Apr 22 2016

Status

approved