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A102555 Smallest number covering bitwise exactly n prime factors. 1
1, 2, 15, 255, 3135, 41055, 440895, 10705695, 242777535, 4360010655 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 26 02:56 EDT 2020. Contains 334613 sequences. (Running on oeis4.)