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%I #28 Oct 07 2022 20:35:16
%S 1,2,3,10,5,11,7,42,15,21,11,43,13,23,29,170,17,47,19,85,31,43,23,171,
%T 45,45,63,87,29,93,31,682,59,81,47,175,37,83,61,341,41,95,43,171,125,
%U 87,47,683,63,173,113,173,53,191,91,343,115,93,59,349,61,95,127,2730
%N Working in base 2, replace n with the concatenation of its prime divisors in increasing order (write answer in base 10).
%H Reinhard Zumkeller, <a href="/A048985/b048985.txt">Table of n, a(n) for n = 1..10000</a>
%H Patrick De Geest, <a href="http://www.worldofnumbers.com/topic1.htm">Home Primes</a>
%e 15 = 3*5 -> 11.101 -> 11101 = 29, so a(15) = 29.
%t f[n_] := FromDigits[ Flatten[ IntegerDigits[ Flatten[ Table[ #1, {#2}] & @@@ FactorInteger@n], 2]], 2]; Array[f, 64] (* _Robert G. Wilson v_, Jun 02 2010 *)
%o (Haskell)
%o -- import Data.List (unfoldr)
%o a048985 = foldr (\d v -> 2 * v + d) 0 . concatMap
%o (unfoldr (\x -> if x == 0 then Nothing else Just $ swap $ divMod x 2))
%o . reverse . a027746_row
%o -- _Reinhard Zumkeller_, Jul 16 2012
%o (Python)
%o from sympy import factorint
%o def a(n):
%o if n == 1: return 1
%o return int("".join(bin(p)[2:]*e for p, e in factorint(n).items()), 2)
%o print([a(n) for n in range(1, 65)]) # _Michael S. Branicky_, Oct 07 2022
%Y Cf. A037276, A048986, A064841.
%Y Cf. A193652, A029744 (record values and where they occur).
%Y Cf. A027746.
%K nonn,easy,nice,base,look
%O 1,2
%A _N. J. A. Sloane_
%E More terms from Sam Alexander (pink2001x(AT)hotmail.com) and _Michel ten Voorde_
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