A063464 Numbers k such that omega(k) = omega(k+2), where omega(k) is the number of distinct prime divisors of k.

2, 3, 5, 7, 9, 10, 11, 12, 17, 18, 20, 22, 23, 24, 25, 26, 27, 29, 33, 34, 36, 38, 41, 44, 46, 47, 48, 50, 52, 54, 55, 56, 59, 63, 71, 72, 74, 75, 79, 80, 81, 85, 86, 91, 92, 93, 94, 96, 98, 101, 104, 106, 107, 115, 116, 117, 122, 125, 130, 133, 134, 137, 138, 141, 142

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harry J. Smith)

Mathematica

Select[Range[200], PrimeNu[#]==PrimeNu[#+2]&] (* Harvey P. Dale, Jun 20 2011 *)

Prog

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

Crossrefs

Cf. A001221, A006049.

Sequence in context: A342190 A175415 A304721 * A341518 A325600 A195921

Adjacent sequences: A063461 A063462 A063463 * A063465 A063466 A063467

Keyword

nonn,easy

Author

Jason Earls, Jul 26 2001

Status

approved