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A220499 Number of line segments in an H tree with n levels that have no correspondence with the toothpicks of the toothpick structure of A139250 after n-th stage. 0
0, 0, 0, 0, 4, 16, 40, 92, 212, 464, 968, 1980, 4016, 8096, 16260, 32612, 65364, 130896, 261960, 524092, 1048368, 2096928, 4194052, 8388324, 16776912, 33554112, 67108516, 134217344, 268435032, 536870428, 1073741252, 2147482996, 4294966612, 8589933904 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

More generally, differences between A000225 and A139250.

LINKS

Table of n, a(n) for n=0..33.

David Applegate, The movie version

Brian Hayes, Joshua Trees and Toothpicks

Brian Hayes, The Toothpick Sequence - Bit-Player

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Wikipedia, H tree

Wikipedia, Toothpick sequence

FORMULA

a(n) = A000225(n) - A139250(n).

EXAMPLE

For n = 0..3, the number of line segments in the H tree equals the number of toothpicks in the toothpick structure of A139250, so a(n) = 0, if 0 <= n <= 3. Note that there is a correspondence between every element from the two structures. For n = 4 the H tree contains 15 line segments, on the other hand the toothpick structure contains only 11 toothpicks. There are four line segments in the H tree that have no correspondence with the toothpicks of the toothpicks structure. They are the four line segments of the last generation that are closer to the center of the H tree, so a(4) = 4.

CROSSREFS

Cf. A000079, A000225, A139250, A139251, A152978, A152980, A153000, A153006.

Sequence in context: A152133 A297361 A210440 * A110477 A007057 A206918

Adjacent sequences:  A220496 A220497 A220498 * A220500 A220501 A220502

KEYWORD

nonn

AUTHOR

Omar E. Pol, Feb 16 2013

STATUS

approved

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Last modified October 20 20:24 EDT 2019. Contains 328273 sequences. (Running on oeis4.)