|
| |
|
|
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
|
| |
|
|
