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A225494 Numbers having only balanced prime factors, cf. A006562. 5
1, 5, 25, 53, 125, 157, 173, 211, 257, 263, 265, 373, 563, 593, 607, 625, 653, 733, 785, 865, 947, 977, 1055, 1103, 1123, 1187, 1223, 1285, 1315, 1325, 1367, 1511, 1747, 1753, 1865, 1907, 2287, 2417, 2677, 2809, 2815, 2903, 2963, 2965, 3035, 3125, 3265, 3307 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..5000

FORMULA

Multiplicative closure of A006562.

PROG

(Haskell)

import Data.Set (singleton, fromList, union, deleteFindMin)

a225494 n = a225494_list !! (n-1)

a225494_list = 1 : h (singleton p) ps [p] where

   (p:ps) = a006562_list

   h s xs'@(x:xs) ys

     | m > x     = h (s `union` (fromList $ map (* x) (1 : ys))) xs ys

     | otherwise = m : h (s' `union` (fromList $ map (* m) ys')) xs' ys'

     where ys' = m : ys; (m, s') = deleteFindMin s

CROSSREFS

Cf. A225493 (strong), A225495 (weak), A225496 (non-balanced).

Sequence in context: A147184 A036133 A062671 * A139479 A078569 A044082

Adjacent sequences:  A225491 A225492 A225493 * A225495 A225496 A225497

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 09 2013

STATUS

approved

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Last modified November 15 18:59 EST 2019. Contains 329149 sequences. (Running on oeis4.)