A007890 Summarize the previous term! (in decreasing order).

1, 11, 21, 1211, 1231, 131221, 132231, 232221, 134211, 14131231, 14231241, 24132231, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221, 14233221

Offset

1,2

Links

Table of n, a(n) for n=1..28.

Onno M. Cain, Sela T. Enin, Inventory Loops (i.e. Counting Sequences) have Pre-period 2 max S_1 + 60, arXiv:2004.00209 [math.NT], 2020.

Formula

From Seiichi Manyama, Aug 18 2020: (Start)

a(1) = 1 and a(n) = A244112(a(n-1)) for n > 1.

a(n) = 14233221 for n >= 13. (End)

Example

For example, the term after 131221 is obtained by saying "one 3, two 2's, three 1's", which gives 13-22-31, i.e. 132231.

Mathematica

Nest[Append[#, FromDigits@ Flatten@ Map[Reverse, Tally@ ReverseSort@ IntegerDigits@ #[[-1]] ] ] &, {1}, 24] (* Michael De Vlieger, Jul 15 2020 *)

Crossrefs

Cf. A005150, A034003, A036058, A244112.

Sequence in context: A005151 A098155 A098154 * A063850 A005150 A001388

Adjacent sequences: A007887 A007888 A007889 * A007891 A007892 A007893

Keyword

nonn,base,easy

Author

Mira Bernstein

Status

approved