login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A045533 Concatenate the n-th and (n+1)st prime. 21
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 (list; graph; refs; listen; history; text; internal format)
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

MAPLE

P:=proc(i) local a, b, n; for n from 1 by 1 to i do a:=ithprime(n); b:=ithprime(n+1); a:=b+a*10^floor(evalf((log10(b)+1), 100)); print(a); od; end: P(100); # Paolo P. Lava, Jan 21 2009

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 22 05:01 EDT 2020. Contains 337950 sequences. (Running on oeis4.)