A030655 Pair up the numbers.

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

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.

Subsequence of A005843.

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