

A101937


Numbers n with omega(n) > omega of 2 nearest larger and 2 nearest smaller neighbors.


2



6, 30, 42, 60, 66, 70, 78, 84, 90, 102, 105, 110, 114, 120, 126, 150, 165, 174, 186, 190, 195, 198, 204, 210, 234, 246, 252, 255, 270, 273, 276, 290, 294, 300, 315, 318, 322, 330, 336, 345, 354, 357, 360, 385, 390, 396, 399, 402, 414, 420
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Prime factors counted without multiplicity.  Harvey P. Dale, Dec 17 2014


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000


EXAMPLE

150 is in the sequence because it has three unique prime factors (2,3 and 5), whereas 148, 149, 151 and 152 each have fewer.


MATHEMATICA

For[i=2, i<1000, If[And[Length[FactorInteger[i2]]<Length[FactorInteger[i]], Length[FactorInteger[i1]]<Length[FactorInteger[i]], Length[FactorInteger[i+1]]<Length[FactorInteger[i]], Length[FactorInteger[i+2]]<Length[FactorInteger[i]]], Print[i]]; i++ ]
gr3Q[{a_, b_, c_, d_, e_}]:=And@@Thread[c>{a, b, d, e}]; Flatten[Position[ Partition[ PrimeNu[Range[500]], 5, 1], _?(gr3Q[#]&)]]+2 (* Harvey P. Dale, Dec 17 2014 *)


CROSSREFS

Cf. A001221, A076763.
Sequence in context: A003062 A327157 A309312 * A101939 A290466 A293188
Adjacent sequences: A101934 A101935 A101936 * A101938 A101939 A101940


KEYWORD

easy,nonn


AUTHOR

Neil Fernandez, Dec 21 2004


STATUS

approved



