A101936 Numbers n with omega(n) = omega of 3 nearest larger and 3 nearest smaller neighbors.

144, 145, 215, 216, 326, 2305, 10283, 16685, 19055, 20215, 21198, 25782, 33335, 35121, 35167, 35205, 39696, 39697, 40272, 41393, 41783, 42345, 42413, 44363, 44364, 44365, 48922, 48923, 48924, 48925, 53737, 54352, 54353, 56017, 56018

Offset

1,1

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Example

10283 is in the sequence because 10280, 10281, 10282, 10283, 10284, 10285, 10286 all have the same number of distinct prime factors (3).

Mathematica

For[i=2, i<100000, If[Length[FactorInteger[i-3]] == Length[FactorInteger[i-2]] == Length[FactorInteger[i-1]] == Length[FactorInteger[i]] == Length[FactorInteger[i+1]] == Length[FactorInteger[i+2]] ==Length[FactorInteger[i+3]], Print[i]]; i++ ]
Select[Range[1300], PrimeNu[#] == PrimeNu[# - 1] == PrimeNu[# - 2] == PrimeNu[# - 3] == PrimeNu[# + 1] == PrimeNu[# + 2] == PrimeNu[# + 3] &] (* G. C. Greubel, May 21 2017 *)

Crossrefs

Cf. A001221, A101932, A101932.

Sequence in context: A093769 A124512 A199546 * A195670 A173065 A044868

Adjacent sequences: A101933 A101934 A101935 * A101937 A101938 A101939

Keyword

easy,nonn

Author

Neil Fernandez, Dec 21 2004

Status

approved