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A030655 Pair up the numbers. 4
12, 34, 56, 78, 910, 1112, 1314, 1516, 1718, 1920, 2122, 2324, 2526, 2728, 2930, 3132, 3334, 3536, 3738, 3940, 4142, 4344, 4546, 4748, 4950, 5152, 5354, 5556, 5758, 5960, 6162, 6364, 6566, 6768, 6970, 7172, 7374, 7576, 7778, 7980, 8182, 8384, 8586 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

That is, a(n) is the concatenation of 2n-1 and 2n. - Charles R Greathouse IV, Aug 07 2012

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

FromDigits[Flatten[IntegerDigits/@{#}]]&/@Partition[Range[90], 2] (* Harvey P. Dale, Sep 28 2011 *)

PROG

(MAGMA) [Seqint(Intseq(n+1) cat Intseq(n)): n in [1..86 by 2]];  // Bruno Berselli, Jun 18 2011

(PARI) a(n)=eval(concat(Str(2*n-1), 2*n)) \\ Charles R Greathouse IV, Jun 18, 2011

CROSSREFS

Cf. A030656.

Sequence in context: A141694 A228595 A077295 * A098080 A068517 A113748

Adjacent sequences:  A030652 A030653 A030654 * A030656 A030657 A030658

KEYWORD

base,nonn,easy

AUTHOR

Maghraoui Abdelkader

EXTENSIONS

More terms from Erich Friedman.

STATUS

approved

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Last modified October 17 22:48 EDT 2018. Contains 316297 sequences. (Running on oeis4.)