|
|
A253910
|
|
Concatenation of n-th prime and n-th nonprime.
|
|
2
|
|
|
21, 34, 56, 78, 119, 1310, 1712, 1914, 2315, 2916, 3118, 3720, 4121, 4322, 4724, 5325, 5926, 6127, 6728, 7130, 7332, 7933, 8334, 8935, 9736, 10138, 10339, 10740, 10942, 11344, 12745, 13146, 13748, 13949, 14950, 15151, 15752, 16354, 16755, 17356, 17957, 18158, 19160, 19362, 19763, 19964, 21165, 22366, 22768, 22969
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
a(5) = 119 because the 5th prime is 11 and the 5th nonprime is 9.
|
|
PROG
|
(PARI) nprime(n)=c=0; k=1; while(k, if(!isprime(k), c++); if(c==n, return(k)); k++)
vector(50, n, eval(concat(Str(prime(n)), Str(nprime(n))))) \\ Derek Orr, Feb 06 2015
(Haskell)
import Data.Function (on)
a253911 n = a253911_list !! (n-1)
a253911_list = map read $
zipWith ((++) `on` show) a018252_list a000040_list :: [Integer]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|