A220498 Number of E-toothpicks (or tridents) added at n-th stage to the structure of the equilateral triangle of A220478.

0, 2, 2, 2, 4, 2, 4, 4, 4, 6, 4, 6, 8, 2, 4, 4, 6, 10, 6, 14, 8, 10, 14, 8, 12, 14, 4, 8, 8, 10, 16, 12, 22, 16, 16, 18, 12, 14, 16, 16, 16, 10, 12, 20, 14, 22, 22, 18, 18, 24, 18, 28, 18, 20, 28, 22, 28, 20, 18, 18, 22, 32, 32, 26, 24, 22, 28, 28, 32, 34, 20, 20, 28

Offset

0,2

Comments

Essentially the first differences of A220478.

Links

Table of n, a(n) for n=0..72.

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Index entries for sequences related to toothpick sequences

Formula

a(n) = 1 + A161331(n+1)/6 = 2*A211976(n).

Crossrefs

Cf. A139250, A139251, A160121, A161330, A161329, A161331, A211974, A211976.

Sequence in context: A005137 A222959 A309441 * A330772 A105681 A368548

Adjacent sequences: A220495 A220496 A220497 * A220499 A220500 A220501

Keyword

nonn

Author

Omar E. Pol, Feb 19 2013

Status

approved