A045533 Concatenate the n-th and (n+1)st prime.

23, 35, 57, 711, 1113, 1317, 1719, 1923, 2329, 2931, 3137, 3741, 4143, 4347, 4753, 5359, 5961, 6167, 6771, 7173, 7379, 7983, 8389, 8997, 97101, 101103, 103107, 107109, 109113, 113127, 127131, 131137

Offset

1,1

Links

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

Formula

a(n) = prime(n)*(10^floor(log_10(prime(n+1)))+1) + prime(n+1). - Conner L. Delahanty, May 10 2014

Mathematica

#[[1]]*10^IntegerLength[#[[2]]]+#[[2]]&/@Partition[Prime[Range[40]], 2, 1] (* Harvey P. Dale, Jun 06 2015 *)

Prog

(Haskell)
a045533 n = a045533_list !! (n-1)
a045533_list = f $ map show a000040_list :: [Integer] where
   f (t:ts@(t':_)) = read (t ++ t') : f ts
-- Reinhard Zumkeller, Apr 20 2012
(PARI) a(n) = eval(concat(Str(prime(n)), Str(prime(n+1)))); \\ Michel Marcus, May 11 2014
(Magma) [Seqint(Intseq(NthPrime(n+1)) cat Intseq(NthPrime(n))): n in [1..50 ] ]; // Marius A. Burtea, Mar 21 2019

Crossrefs

Cf. A077800, A095958 (subsequence), A030461 (primes).

Sequence in context: A223606 A120147 A166499 * A329179 A154114 A163384

Adjacent sequences: A045530 A045531 A045532 * A045534 A045535 A045536

Keyword

nonn,base

Author

N. J. A. Sloane, Dec 11 1999

Extensions

Offset changed to 1, in agreement with (almost?) all references to this sequence, by M. F. Hasler

Status

approved