A127008 a(0)=1. For n>=1, n-th run consists of the integers in descending order of a(n-1)+n-1 through n.

1, 1, 2, 4, 3, 7, 6, 5, 4, 7, 6, 5, 12, 11, 10, 9, 8, 7, 6, 12, 11, 10, 9, 8, 7, 12, 11, 10, 9, 8, 12, 11, 10, 9, 16, 15, 14, 13, 12, 11, 10, 16, 15, 14, 13, 12, 11, 16, 15, 14, 13, 12, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 24, 23

Offset

0,3

Links

Table of n, a(n) for n=0..76.

Example

The sequence grouped by descending runs, where the n-th run, for n>=1, consists of a(n-1) integers: 1, (1), (2), (4, 3), (7, 6, 5, 4), (7, 6, 5), (12, 11, 10, 9, 8, 7, 6), (12, 11, 10, 9, 8, 7), (12, 11, 10, 9, 8), (12, 11, 10, 9), ...

Mathematica

f[l_List] := Block[{n = Length[l]}, Append[l, Range[Flatten[l][[n]] + n - 1, n, -1]]]; Flatten@Nest[f, {{1}}, 15] (* Ray Chandler, Jan 04 2007 *)

Crossrefs

Sequence in context: A361939 A371237 A108228 * A199535 A064274 A035513

Adjacent sequences: A127005 A127006 A127007 * A127009 A127010 A127011

Keyword

easy,nonn

Author

Leroy Quet, Jan 02 2007

Extensions

Extended by Ray Chandler, Jan 04 2007

Status

approved