cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A216955 Triangle read by rows: T(n,k) (n>=1, 1<=k<=n) = number of binary sequences of length n and curling number k.

Original entry on oeis.org

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
Offset: 1

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Author

N. J. A. Sloane, Sep 26 2012

Keywords

Comments

For definition of curling number see A216730.
"Binary" sequence means two-valued. 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

Examples

			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.

Extensions

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