A063464 - OEIS

%I #23 Dec 02 2023 09:12:50

%S 2,3,5,7,9,10,11,12,17,18,20,22,23,24,25,26,27,29,33,34,36,38,41,44,

%T 46,47,48,50,52,54,55,56,59,63,71,72,74,75,79,80,81,85,86,91,92,93,94,

%U 96,98,101,104,106,107,115,116,117,122,125,130,133,134,137,138,141,142

%N Numbers k such that omega(k) = omega(k+2), where omega(k) is the number of distinct prime divisors of k.

%H Amiram Eldar, <a href="/A063464/b063464.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harry J. Smith)

%t Select[Range[200],PrimeNu[#]==PrimeNu[#+2]&] (* _Harvey P. Dale_, Jun 20 2011 *)

%o (PARI) j=[]; for(n=1,350, if(omega(n)==omega(n+2),j=concat(j,n))); j

%o (PARI) { n=0; for (m=1, 10^9, if (omega(m) == omega(m + 2), write("b063464.txt", n++, " ", m); if (n==1000, break)) ) } \\ _Harry J. Smith_, Aug 22 2009

%Y Cf. A001221, A006049.

%K nonn,easy

%O 1,1

%A _Jason Earls_, Jul 26 2001