

A194442


Number of toothpicks and Dtoothpicks after nth stage in the Dtoothpick "narrow" triangle of the second kind.


18



0, 1, 3, 7, 11, 15, 19, 26, 34, 38, 42, 50, 62, 70, 78, 91, 107, 111, 115, 123, 135, 151, 167, 187, 211, 223, 231, 247, 275, 291, 307, 332, 364, 368, 372, 380, 392, 408, 424, 446, 478, 504, 524, 548, 588, 620, 660, 693, 741, 761, 769, 785, 813, 853, 897, 947
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OFFSET

0,3


COMMENTS

If n = 2^k, k >= 1, then the structure looks like an isosceles triangle. For the Dtoothpick "wide" triangle of the second kind see A194440.
The structure is essentially one of the wedges of several Dtoothpick structures. For more information see A194270. The first differences (A194443) give the number of toothpicks or Dtoothpicks added at nth stage.  Omar E. Pol, Mar 28 2013


LINKS

Table of n, a(n) for n=0..55.
Omar E. Pol, Illustration of the structure after 32 stages
Omar E. Pol, Illustration of the structure after 64 stages
N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS
Index entries for sequences related to toothpick sequences


CROSSREFS

Cf. A047999, A139250, A160120, A160406, A161830, A194270, A194277, A194440, A194443, A194444, A194694, A194695, A194697, A220496, A220522.
Sequence in context: A292657 A277675 A220496 * A220522 A220526 A034934
Adjacent sequences: A194439 A194440 A194441 * A194443 A194444 A194445


KEYWORD

nonn


AUTHOR

Omar E. Pol, Aug 29 2011


STATUS

approved



