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A001388 Describe the previous term (in base 3)!. 4
1, 11, 21, 1211, 111221, 1012211, 1110112221, 101102110211, 111021101221101221, 1011012211011222110112211, 1110211011222110211022110212221, 10110122110211022110122110222110121110211 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

John Cerkan, Table of n, a(n) for n = 1..23

EXAMPLE

To get the 6th term, for example, note that the 5th term has three (10 in ternary!) 1's, two (2) 2's and one (1) 1, giving 10 1 2 2 1 1.

MATHEMATICA

a[1] := 1; a[n_] := a[n] = FromDigits[Flatten[{IntegerDigits[Length[#], 3], First[#]}& /@ Split[IntegerDigits[a[n-1]]]]]; Map[a, Range[25]] (* Peter J. C. Moses, Mar 24 2013 *)

CROSSREFS

Cf. A005150.

Sequence in context: A007890 A063850 A005150 * A110393 A202627 A257491

Adjacent sequences:  A001385 A001386 A001387 * A001389 A001390 A001391

KEYWORD

nonn,base,easy

AUTHOR

Thomas L. York

STATUS

approved

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Last modified August 19 13:00 EDT 2017. Contains 290807 sequences.