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A048985 Working in base 2, replace n with the concatenation of its prime divisors in increasing order (write answer in base 10). 10
1, 2, 3, 10, 5, 11, 7, 42, 15, 21, 11, 43, 13, 23, 29, 170, 17, 47, 19, 85, 31, 43, 23, 171, 45, 45, 63, 87, 29, 93, 31, 682, 59, 81, 47, 175, 37, 83, 61, 341, 41, 95, 43, 171, 125, 87, 47, 683, 63, 173, 113, 173, 53, 191, 91, 343, 115, 93, 59, 349, 61, 95, 127, 2730 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

P. De Geest, Home Primes

EXAMPLE

15 = 3*5 -> 11.101 -> 11101 = 29, so a(15) = 29.

MATHEMATICA

f[n_] := FromDigits[ Flatten[ IntegerDigits[ Flatten[ Table[ #1, {#2}] & @@@ FactorInteger@n], 2]], 2]; Array[f, 64] (* Robert G. Wilson v, Jun 02 2010 *)

PROG

(Haskell)

-- import Data.List (unfoldr)

a048985 = foldr (\d v -> 2 * v + d) 0 . concatMap

   (unfoldr (\x -> if x == 0 then Nothing else Just $ swap $ divMod x 2))

   . reverse . a027746_row

-- Reinhard Zumkeller, Jul 16 2012

CROSSREFS

Cf. A037276, A048986, A064841.

Cf. A193652, A029744 (record values and where they occur).

Cf. A027746.

Sequence in context: A213962 A216937 A230625 * A112417 A139693 A182076

Adjacent sequences:  A048982 A048983 A048984 * A048986 A048987 A048988

KEYWORD

nonn,easy,nice,base,look

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Sam Alexander (pink2001x(AT)hotmail.com) and Michel ten Voorde (seqfan(AT)tenvoorde.org)

STATUS

approved

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Last modified June 25 20:26 EDT 2017. Contains 288730 sequences.