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A076251 omega(n) = omega(n-1) + omega(n-2), where omega(n) is the number of distinct prime factors of n. 4
3, 6, 10, 18, 30, 33, 42, 60, 66, 84, 90, 102, 105, 110, 114, 126, 129, 130, 138, 150, 165, 168, 174, 180, 195, 198, 210, 228, 234, 252, 264, 270, 273, 285, 290, 294, 315, 318, 330, 345, 348, 354, 360, 385, 399, 402, 420, 434, 450, 462, 465, 468, 480, 504 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

EXAMPLE

omega(18) = 2 = 1 + 1 = omega(17) + omega(16), so 18 belongs to the sequence.

MATHEMATICA

omega[n_] := Length[FactorInteger[n]]; Select[Range[3, 10^3], omega[ # ] == omega[ # - 1] + omega[ # - 2] &]

CROSSREFS

Cf. A001221.

Sequence in context: A182152 A170803 A182908 * A261631 A029864 A075111

Adjacent sequences:  A076248 A076249 A076250 * A076252 A076253 A076254

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Nov 04 2002

STATUS

approved

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Last modified March 23 17:19 EDT 2019. Contains 321432 sequences. (Running on oeis4.)