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%I #30 Jan 21 2016 16:38:05
%S 0,0,0,0,4,16,40,92,212,464,968,1980,4016,8096,16260,32612,65364,
%T 130896,261960,524092,1048368,2096928,4194052,8388324,16776912,
%U 33554112,67108516,134217344,268435032,536870428,1073741252,2147482996,4294966612,8589933904
%N 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.
%C More generally, differences between A000225 and A139250.
%H David Applegate, <a href="/A139250/a139250.anim.html">The movie version</a>
%H Brian Hayes, <a href="http://bit-player.org/2013/joshua-trees-and-toothpicks">Joshua Trees and Toothpicks</a>
%H Brian Hayes, <a href="http://bit-player.org/extras/toothpicks/toothpicks.html">The Toothpick Sequence - Bit-Player</a>
%H N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/H_tree">H tree</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Toothpick_sequence">Toothpick sequence</a>
%F a(n) = A000225(n) - A139250(n).
%e 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.
%Y Cf. A000079, A000225, A139250, A139251, A152978, A152980, A153000, A153006.
%K nonn
%O 0,5
%A _Omar E. Pol_, Feb 16 2013
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