

A216951


Let S be a string of n 2's and 3's, with curling number k, which means S = XY^k where k is maximized; a(n) = number of S for which X must be taken to be the empty string.


2



2, 2, 2, 4, 2, 8, 2, 10, 8, 14, 2, 40, 2, 40, 32, 88, 2, 192, 2, 324, 100, 564, 2, 1356, 32, 2226, 370, 4564, 2, 9656, 2, 17944, 1450, 35424, 152, 74182, 2, 141628, 5774, 284342, 2, 578022, 2, 1134518, 23576, 2265394, 2, 4580468, 128, 9062280, 92236, 18129626
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

See A216730 for definition of curling number.


LINKS

Lars Blomberg, Table of n, a(n) for n = 1..120
B. Chaffin, J. P. Linderman, N. J. A. Sloane and Allan Wilks, On Curling Numbers of Integer Sequences, arXiv:1212.6102, Dec 25 2012.
B. Chaffin, J. P. Linderman, N. J. A. Sloane and Allan Wilks, On Curling Numbers of Integer Sequences, Journal of Integer Sequences, Vol. 16 (2013), Article 13.4.3.
Index entries for sequences related to curling numbers


EXAMPLE

For n=6, there are 8 strings S that satisfy the condition:
222222, k=6, Y=2
223223, k=2, Y=223
232232, k=2, Y=232
232323, k=3, Y=23
and 4 more by exchanging 2 and 3. Note that 233233 with k=2 is not on the list, because we could choose X empty, Y=233 or X=2332, Y=3, and the latter avoids taking X to be empty.


CROSSREFS

Cf. A216730, A216952.
Sequence in context: A278242 A035580 A135293 * A320305 A064025 A182154
Adjacent sequences: A216948 A216949 A216950 * A216952 A216953 A216954


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Sep 24 2012


EXTENSIONS

More terms from Lars Blomberg, Nov 02 2016


STATUS

approved



