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A076252 omega(n) = omega(n-1) + omega(n-2) + omega(n-3), where omega(n) is the number of distinct prime factors of n. 1
2310, 3990, 4290, 6090, 6270, 10010, 11550, 12810, 13650, 17094, 17940, 18270, 19380, 21930, 22110, 22770, 23100, 24990, 25410, 27300, 28644, 30090, 32214, 32604, 34034, 34314, 35340, 35880, 37310, 38190, 38570, 38640, 39270, 39780 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
omega(2310) = 5 = 1 + 2 + 2 = omega(2309) + omega(2308) + omega(2307), so 2310 belongs to the sequence.
MATHEMATICA
omega[n_] := Length[FactorInteger[n]]; a = {}; Do[If[omega[n] == omega[n - 1] + omega[n - 2] + omega[n - 3], a = Append[a, n]], {n, 1, 10^5}]; a
Flatten[Position[Partition[PrimeNu[Range[40000]], 4, 1], _?(#[[4]] == Total[ Take[ #, 3]]&), {1}, Heads->False]]+3 (* Harvey P. Dale, Oct 31 2016 *)
CROSSREFS
Cf. A001221.
Sequence in context: A046387 A136154 A258360 * A264718 A147572 A046303
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Nov 04 2002
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)