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A062974
Numbers k such that omega(k+1) < 2*omega(k), where omega(k) is the number of distinct prime divisors of k.
2
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
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
KEYWORD
nonn
AUTHOR
Jason Earls, Jul 26 2001
STATUS
approved