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A316499 Intersection of A001694 and A195069. 1
2048, 9216, 13824, 20736, 25600, 31104, 46656, 50176, 64000, 69984, 104976, 115200, 123904, 157464, 160000, 172800, 173056, 175616, 177147, 225792, 236196, 259200, 288000, 338688, 388800, 400000, 432000, 508032, 557568, 583200, 614656, 627200, 648000, 681472, 720000, 762048, 778752, 790272 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Powerful(1) numbers k such that A046660(k) = 10.

These are the "primitive" members of A195069, in the sense that A195059 is the set of numbers k*m where k is in this sequence and m is squarefree and coprime to k.

LINKS

Robert Israel, Table of n, a(n) for n = 1..2528

EXAMPLE

a(3)=13824 is a member because 13824= 2^9*3^3, 9 and 3 are both greater than 1 and (9-1)+(3-1)=10.

MAPLE

N:= 10^6: # to get all terms <= N

p:= 1:

for i from 1 to 10 do F[i]:= {} od:

do

  p:= nextprime(p);

  if p^2 > N then break fi;

  for i from min(10, floor(log[p](N))-1) to 2 by -1 do F[i]:= F[i] union

    select(`<=`, `union`({p^(i+1)}, seq(map(t -> p^(i+1-j)*t, F[j]), j=1..i-1)), N)

  od;

  F[1]:= F[1] union {p^2};

od:

sort(convert(F[10], list));

CROSSREFS

Cf. A001694, A046660, A195069.

Sequence in context: A234881 A220584 A195069 * A135290 A204837 A100629

Adjacent sequences:  A316496 A316497 A316498 * A316500 A316501 A316502

KEYWORD

nonn

AUTHOR

Robert Israel, Jul 04 2018

STATUS

approved

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Last modified June 23 11:59 EDT 2021. Contains 345398 sequences. (Running on oeis4.)