

A216955


Triangle read by rows: T(n,k) (n>=1, 1<=k<=n) = number of binary sequences of length n and curling number k.


21



2, 2, 2, 4, 2, 2, 6, 6, 2, 2, 12, 12, 4, 2, 2, 20, 26, 10, 4, 2, 2, 40, 52, 20, 8, 4, 2, 2, 74, 110, 38, 18, 8, 4, 2, 2, 148, 214, 82, 36, 16, 8, 4, 2, 2, 286, 438, 164, 70, 34, 16, 8, 4, 2, 2, 572, 876, 328, 140, 68, 32, 16, 8, 4, 2, 2, 1124, 1762, 660, 286, 134, 66, 32, 16, 8, 4, 2, 2, 2248, 3524, 1320, 572, 268, 132, 64, 32, 16, 8, 4, 2, 2
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

For definition of curling number see A216730.
"Binary" sequence means twovalued. It doesn't matter if the alphabet is {0,1} or {2,3}.
It appears that reversed rows converge to the sequence formed by the even terms of A090129.  Omar E. Pol, Nov 20 2012


LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..5460
Benjamin Chaffin, John P. Linderman, N. J. A. Sloane and Allan Wilks, First 104 rows of A216955
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

Triangle begins:
2,
2, 2,
4, 2, 2,
6, 6, 2, 2,
12, 12, 4, 2, 2,
20, 26, 10, 4, 2, 2,
40, 52, 20, 8, 4, 2, 2,
74, 110, 38, 18, 8, 4, 2, 2,
148, 214, 82, 36, 16, 8, 4, 2, 2,
286, 438, 164, 70, 34, 16, 8, 4, 2, 2,
...


CROSSREFS

Leading columns are A122536 (or A093371), A217211, A217212. Cf. A216956, A217943.
Sequence in context: A049627 A278223 A134058 * A086973 A240131 A029658
Adjacent sequences: A216952 A216953 A216954 * A216956 A216957 A216958


KEYWORD

nonn,tabl


AUTHOR

N. J. A. Sloane, Sep 26 2012


EXTENSIONS

Extended to 104 rows by N. J. A. Sloane, Nov 15 2012


STATUS

approved



