A171094 a(n) is the string of integers S(n) concatenated together with no commas, where S(1)=1; for even n, S(n) is obtained from S(n-1) by inserting n after 1; and for odd n>1, S(n) = n,S(n-1).

1, 12, 312, 3142, 53142, 531642, 7531642, 75318642, 975318642, 97531108642, 1197531108642, 119753112108642, 13119753112108642, 1311975311412108642, 151311975311412108642, 15131197531161412108642

Offset

1,2

Links

Table of n, a(n) for n=1..16.

M. S. Coleman, Asymptotic enumeration in pattern avoidance and in the theory of set partitions and asymptotic uniformity.

Mathematica

f[n_] := FromDigits@ Flatten[ IntegerDigits /@ Reverse[{2 Range[n/2], 2 Range[(n + 1)/2] - 1}, {1, 2}]]; Array[f, 16] (* Robert G. Wilson v, Sep 18 2010 *)

Crossrefs

Cf. A171093. - Robert G. Wilson v, Sep 18 2010

Sequence in context: A304126 A263668 A053064 * A060010 A129583 A323839

Adjacent sequences: A171091 A171092 A171093 * A171095 A171096 A171097

Keyword

nonn,base,easy

Author

N. J. A. Sloane, Sep 18 2010

Extensions

More terms from Robert G. Wilson v, Sep 18 2010

Status

approved