OFFSET
1,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Infinitary Divisor
EXAMPLE
For n=60=3*4*5, no subproduct is 2,6,10,30. They are all non-infinitary divisors of 60. Since 60=A162643(17) then a(17) = 2.
MATHEMATICA
Map[First@ Complement[Divisors@ #, If[# == 1, {1}, Sort@ Flatten@ Outer[Times, Sequence @@ (FactorInteger[#] /. {p_, m_Integer} :> p^Select[Range[0, m], BitOr[m, #] == m &])]]] &, Select[Range@ 198, ! IntegerQ@ Log2@ DivisorSigma[0, #] &]] (* Michael De Vlieger, Feb 24 2017, after Paul Abbott at A077609 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Feb 24 2017
STATUS
approved