A062974 Numbers k such that omega(k+1) < 2*omega(k), where omega(k) is the number of distinct prime divisors of k.

2, 3, 4, 6, 7, 8, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 26, 28, 30, 31, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100

Offset

1,1

Comments

A001221(a(n)+1) < 2*A001221(a(n)).

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Prog

(PARI) j=[]; for(n=1, 200, if(omega(n+1)<2*omega(n), j=concat(j, n))); j
(Haskell)
import Data.List (findIndices)
a062974 n = a062974_list !! (n-1)
a062974_list = map (+ 1) $ findIndices (< 0) $
   zipWith (-) (tail a001221_list) $ map (* 2) a001221_list
-- Reinhard Zumkeller, Jan 22 2013

Crossrefs

Cf. A006049 (subsequence).

Sequence in context: A294652 A352882 A320143 * A329399 A329396 A328595

Adjacent sequences: A062971 A062972 A062973 * A062975 A062976 A062977

Keyword

nonn

Author

Jason Earls, Jul 26 2001

Status

approved