%N Toothpick pyramid (see Comments lines for definition).
%C The toothpick pyramid is a three-dimensional version of the toothpick triangle A160406.
%C The sequence gives the number of toothpicks after n rounds. A160409 (the first differences) gives the number added at the n-th round.
%C See also the entry A139250 for more information about the toothpick sequences.
%H David Applegate, Omar E. Pol and N. J. A. Sloane, <a href="http://neilsloane.com/doc/tooth.pdf">The Toothpick Sequence and Other Sequences from Cellular Automata</a>
%H N. J. A. Sloane, <a href="http://neilsloane.com/doc/toothlist.html">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a>
%Y Cf. A139250, A139251, A160160, A160406, A160407, A160409.
%A _Omar E. Pol_, May 23 2009, Jun 06 2009