A253910 Concatenation of n-th prime and n-th nonprime.

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

Offset

1,1

Comments

Concatenate A000040(n) and A018252(n).

Links

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

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]
-- Reinhard Zumkeller, Feb 09 2015

Crossrefs

Cf. A000040, A018252, A038530, A045532, A075110, A106582, A138821, A138822, A253911.

Sequence in context: A082483 A075735 A053409 * A144205 A261408 A008946

Adjacent sequences: A253907 A253908 A253909 * A253911 A253912 A253913

Keyword

nonn,base,easy

Author

Omar E. Pol, Feb 06 2015

Status

approved