|
| |
|
|
A072103
|
|
Sorted perfect powers a^b for a, b > 1 with duplication.
|
|
2
|
|
|
|
4, 8, 9, 16, 16, 25, 27, 32, 36, 49, 64, 64, 64, 81, 81, 100, 121, 125, 128, 144, 169, 196, 216, 225, 243, 256, 256, 256, 289, 324, 343, 361, 400, 441, 484, 512, 512, 529, 576, 625, 625, 676, 729, 729, 729, 784, 841, 900, 961, 1000, 1024, 1024, 1024, 1089
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
2,1
|
|
|
LINKS
|
_Reinhard Zumkeller_, Table of n, a(n) for n = 2..10000
Eric Weisstein's World of Mathematics, Perfect Power
|
|
|
MATHEMATICA
|
nn=60; Take[Sort[#[[1]]^#[[2]]&/@Tuples[Range[2, nn], 2]], nn] (* Harvey P. Dale, Oct 03 2012 *)
|
|
|
PROG
|
(Haskell)
import Data.Set (singleton, findMin, deleteMin, insert)
a072103 n = a072103_list !! (n-1)
a072103_list = f 9 3 $ Set.singleton (4, 2) where
f zz z s
| xx < zz = xx : f zz z (Set.insert (x*xx, x) $ Set.deleteMin s)
| otherwise = zz : f (zz+2*z+1) (z+1) (Set.insert (z*zz, z) s)
where (xx, x) = Set.findMin s
-- Reinhard Zumkeller, Oct 04 2012
|
|
|
CROSSREFS
|
Cf. A001597.
Sequence in context: A020217 A141066 A018196 * A004756 A153034 A106840
Adjacent sequences: A072100 A072101 A072102 * A072104 A072105 A072106
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Eric W. Weisstein, Jun 18, 2002
|
|
|
STATUS
|
approved
|
| |
|
|
