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A045533 Concatenate the n-th and (n+1)st prime. 20
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(log10(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

CROSSREFS

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

Sequence in context: A223606 A120147 A166499 * A154114 A163384 A059798

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

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Last modified August 22 07:02 EDT 2017. Contains 290943 sequences.