

A218875


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


3



2, 2, 0, 4, 2, 0, 6, 4, 2, 0, 10, 12, 4, 2, 0, 20, 20, 8, 4, 2, 0, 36, 52, 20, 8, 4, 2, 0, 72, 98, 36, 16, 8, 4, 2, 0, 142, 214, 76, 36, 16, 8, 4, 2, 0, 280, 414, 160, 68, 32, 16, 8, 4, 2, 0, 560, 870, 326, 140, 68, 32, 16, 8, 4, 2, 0, 1114, 1720, 640, 276, 132, 64, 32, 16, 8, 4, 2, 0
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS

Table of n, a(n) for n=1..78.
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.
N. J. A. Sloane, First 36 rows of table
Index entries for sequences related to curling numbers


FORMULA

The triangle in A218869 is the sum of triangles A218875 and A218876.


EXAMPLE

Triangle begins:
[2],
[2, 0],
[4, 2, 0],
[6, 4, 2, 0],
[10, 12, 4, 2, 0],
[20, 20, 8, 4, 2, 0],
[36, 52, 20, 8, 4, 2, 0],
[72, 98, 36, 16, 8, 4, 2, 0],
[142, 214, 76, 36, 16, 8, 4, 2, 0],
[280, 414, 160, 68, 32, 16, 8, 4, 2, 0],
...


CROSSREFS

Cf. A216955, A218869, A218876. First column is A216958.
Sequence in context: A253243 A201396 A005881 * A218869 A144458 A098268
Adjacent sequences: A218872 A218873 A218874 * A218876 A218877 A218878


KEYWORD

nonn,tabl


AUTHOR

N. J. A. Sloane, Nov 15 2012


STATUS

approved



