login
A085706
Squarefree numbers sandwiched between two brilliant numbers.
0
5, 870, 1158, 24882, 35238, 37770, 39270, 46002, 47262, 48930, 51810, 55482, 59910, 62430, 65622, 69870, 76458, 85542, 88638, 90942, 91338, 91362, 91830, 93018, 93882, 94362, 95298, 97638, 98070, 99510, 101262, 103602, 112038, 116022, 118230
OFFSET
1,1
EXAMPLE
a(3)=1158 because it is squarefree and 1157 = 13*89 is brilliant as is
1159 = 19*61.
MATHEMATICA
sfnQ[{a_, b_, c_}]:=Module[{a1=FactorInteger[a][[All, 1]], c1= FactorInteger[ c][[All, 1]]}, Length[a1]==Length[c1]==2&&PrimeOmega[a]== PrimeOmega[c] == 2&&IntegerLength[a1[[1]]]==IntegerLength[a1[[2]]]&&IntegerLength[ c1[[1]]] == IntegerLength[c1[[2]]]&&SquareFreeQ[b]]; Join[{5}, Select[ Partition[Range[120000], 3, 1], sfnQ][[All, 2]]] (* Harvey P. Dale, Nov 26 2016 *)
CROSSREFS
Cf. A078972.
Sequence in context: A198402 A214450 A332185 * A190350 A135084 A206356
KEYWORD
nonn
AUTHOR
Jason Earls, Jul 18 2003
STATUS
approved