

A294960


Snowflake (or Etoothpick) sequence of the second kind (see Comments lines for definition).


1



0, 2, 8, 14, 20, 26, 44, 50, 68, 86, 104, 110, 128, 158, 176, 206, 260, 278, 320, 350, 392, 410, 452, 494, 548, 614
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OFFSET

0,2


COMMENTS

This has essentially the same rules as the snowflake sequence A161330, but here there is an additional rule: there are no Etoothpicks of the same generation that share the endpoint of two parallel components.
The structure is lighter than the structure of A161330 from which differs at a(7).
Note that, on the infinite triangular grid, an Etoothpick can be represented as a polyedge with three components. In this case, at the nth round, the structure is a polyedge with 3*a(n) components.
An Etoothpick looks like a bird's footprint (or more generally a dinosaur's footprint).
a(n) gives the number of Etoothpicks in the structure after n rounds.
A294961(n) is the number of Etoothpicks added at the nth round, n >= 1.  Omar E. Pol, Apr 15 2018


LINKS

Table of n, a(n) for n=0..25.
N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS
Index entries for sequences related to cellular automata
Index entries for sequences related to toothpick sequences


CROSSREFS

Another version of A161330.
Cf. A139250, A160120, A161328, A294961 (first differences).
Sequence in context: A117104 A082933 A016933 * A101959 A241003 A133229
Adjacent sequences: A294957 A294958 A294959 * A294961 A294962 A294963


KEYWORD

nonn,more


AUTHOR

Omar E. Pol, Nov 12 2017


STATUS

approved



