OFFSET
1,1
MATHEMATICA
f[n_] := FromDigits[IntegerDigits[n, 2], 4]; s = Array[f, 300, 2]; div[a_, b_] := Divisible[a, b] && a > b; n = 1; s0 = s; While[Length[s] > n, s = Select[s, ! div[#, s[[n]]] &]; n++]; s1 = Complement[s0, s]; aQ[n_, s_] := Times @@ (s^(IntegerExponent[n, #] & /@ s)) == n; Select[s1, ! aQ[#, s] &] (* Amiram Eldar, Aug 31 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Nov 20 2008, Jun 11 2009
EXTENSIONS
a(12)-a(14) inserted and more terms added by Amiram Eldar, Aug 31 2019
STATUS
approved