

A217943


Triangle read by rows: T(n,k) = 2*C(n1,k)C(n,k) for k<n, T(n,n)=2, where C(n,k) = A216955(n,k).


2



2, 2, 0, 2, 2, 2, 2, 2, 2, 0, 0, 0, 2, 2, 4, 2, 2, 0, 2, 2, 0, 0, 0, 0, 0, 2, 2, 6, 6, 2, 2, 0, 0, 2, 2, 0, 6, 6, 0, 0, 0, 0, 2, 2, 10, 10, 0, 2, 2, 0, 0, 0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 20, 10, 4, 6, 2, 2, 0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2
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OFFSET

2,1


LINKS

Table of n, a(n) for n=2..91.
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, Rows 2 through 48 of A217943
Index entries for sequences related to curling numbers


EXAMPLE

Triangle begins:
[2, 2]
[0, 2, 2]
[2, 2, 2, 2]
[0, 0, 0, 2, 2]
[4, 2, 2, 0, 2, 2]
[0, 0, 0, 0, 0, 2, 2]
[6, 6, 2, 2, 0, 0, 2, 2]
[0, 6, 6, 0, 0, 0, 0, 2, 2]
[10, 10, 0, 2, 2, 0, 0, 0, 2, 2]
[0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2]
[20, 10, 4, 6, 2, 2, 0, 0, 0, 0, 2, 2]
...


CROSSREFS

Cf. A216955.
The nonzero entries in the first column form A216958.
Sequence in context: A354186 A127527 A356583 * A177225 A236306 A153239
Adjacent sequences: A217940 A217941 A217942 * A217944 A217945 A217946


KEYWORD

sign,tabf


AUTHOR

N. J. A. Sloane, following a suggestion from Allan Wilks, Oct 25 2012


STATUS

approved



