

A187212


Qtoothpick sequence in the first quadrant.


8



0, 1, 3, 5, 9, 13, 21, 31, 39, 43, 51, 63, 75, 91, 119, 149, 165, 169, 177, 189, 201, 217, 245, 277, 297, 313, 341, 377, 417, 477, 565, 643, 675, 679, 687, 699, 711, 727, 755, 787, 807, 823, 851, 887, 927, 987, 1075
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OFFSET

0,3


COMMENTS

At stage 0, we start with no Qtoothpicks.
At stage 1, we place a Qtoothpick centered at (1,0) with its endpoints at (0,0) and (1,1).
At stage 2, we place two Qtoothpicks.
The sequence gives the number of Qtoothpicks in the structure after nth stage.
A187213 gives the number of Qtoothpicks added at nth stage.
Note that starting from (0,1), with the first Qtoothpick centered at (1,1), we have the toothpick sequence A139250.
Also, gullwing sequence on the semiinfinite square grid, since a "gull" is formed by two Qtoothpicks. The sequence gives the number of "gulls" (or Gtoothpicks) in the structure after nth stage. See A187220.  Omar E. Pol, Mar 30 2011


LINKS



FORMULA

It appears that a(n) = A139250(n)  2*A059939(n), for n >= 1.  Omar E. Pol, Mar 29 2011


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



