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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 * A337183 A112417 A139693

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

STATUS

approved

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Last modified April 14 22:43 EDT 2021. Contains 342963 sequences. (Running on oeis4.)