A102555 Smallest number covering bitwise exactly n prime factors.

1, 2, 15, 255, 3135, 41055, 440895, 10705695, 242777535, 4360010655

Offset

0,2

Comments

A102550(a(n))=n and A102550(m) < n for m < a(n).

a(10) <= 287901348735. - Amiram Eldar, Feb 04 2019

Links

Table of n, a(n) for n=0..9.

Mathematica

npfQ[k_, n_] := Module[{f=FactorInteger[k][[;; , 1]]}, Length[f] == n && Count[ BitAnd[k, f] - f, 0] == n]; s={1}; Do[k=2; While[!npfQ[k, n], k++]; AppendTo[s, k], {n, 1, 7}]; s (* Amiram Eldar, Feb 04 2019 *)

Crossrefs

Cf. A007088, A004676, A102550.

Sequence in context: A292798 A221100 A203310 * A264907 A195737 A192567

Adjacent sequences: A102552 A102553 A102554 * A102556 A102557 A102558

Keyword

nonn,base,more

Author

Reinhard Zumkeller, Jan 14 2005

Extensions

Two more terms and "base" keyword from Max Alekseyev, Sep 13 2009

Offset 0 and a(7)-a(9) from Amiram Eldar, Feb 04 2019

Status

approved