OFFSET
1,2
COMMENTS
FORMULA
a(n) <= A061720(n-1) for all n >= 1.
MATHEMATICA
With[{s = FoldList[Times, 1, Prime@ Range@ 7]}, Array[Boole[# == 2] + Count[Range[s[[# - 1]], s[[#]] - 1], _?(Times @@ Boole@ Map[First@ # > Last@ # &, FactorInteger@ #] > 0 &)] &, Length@ s - 1, 2]] (* Michael De Vlieger, Oct 17 2019 *)
PROG
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Antti Karttunen, Oct 17 2019
STATUS
approved