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A073646 Least number formed by concatenating the prime factors of n in base 10. 5
1, 2, 3, 22, 5, 23, 7, 222, 33, 25, 11, 223, 13, 27, 35, 2222, 17, 233, 19, 225, 37, 112, 23, 2223, 55, 132, 333, 227, 29, 235, 31, 22222, 113, 172, 57, 2233, 37, 192, 133, 2225, 41, 237, 43, 1122, 335, 223, 47, 22223, 77, 255, 173, 1322, 53, 2333, 115, 2227 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n)<=A037276(n) for all n and a(n)=A037276(n) for n<22, a(22) = a(2*11) = 112 <> A037276(22) = 211.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

Sort {A027746(n,k): k=1..A001222(n)} lexicographically and concatenate. - Reinhard Zumkeller, Jul 13 2013

EXAMPLE

a(6) = a(2*3) = 23 < 32; a(66) = a(2*3*11) = 1123 < 1132 < 2113 < 2311 < 3112 < 3211.

MATHEMATICA

con[n_, k_] := Nest[Join[{#}, {n}] &, n, k - 1]; Table[Min[FromDigits /@ Flatten /@ IntegerDigits[Permutations[Flatten[con @@@ FactorInteger[n]]]]], {n, 56}] (* Jayanta Basu, Jul 04 2013 *)

PROG

(Haskell)

import Data.List (sort)

a073646 :: Integer -> Integer

a073646 = read . concat . sort . map show . a027746_row

-- Reinhard Zumkeller, Jul 13 2013

CROSSREFS

Different from A037276. Cf. A084797.

Sequence in context: A080670 A288532 A073647 * A037276 A068190 A084796

Adjacent sequences:  A073643 A073644 A073645 * A073647 A073648 A073649

KEYWORD

nonn,base,look

AUTHOR

Reinhard Zumkeller, Aug 29 2002

STATUS

approved

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Last modified December 16 12:31 EST 2018. Contains 318160 sequences. (Running on oeis4.)