A211016 - OEIS

A211016

Triangle read by rows: T(n,k) = number of squares and rectangles of area 2^(k-1) after 2^n stages in the toothpick structure of A139250, n>=1, k>=1, assuming the toothpicks have length 2.

0, 0, 4, 8, 12, 4, 40, 52, 12, 4, 168, 212, 52, 12, 4, 680, 852, 212, 52, 12, 4, 2728, 3412, 852, 212, 52, 12, 4, 10920, 13652, 3412, 852, 212, 52, 12, 4, 43688, 54612, 13652, 3412, 852, 212, 52, 12, 4, 174760, 218452, 54612, 13652, 3412, 852, 212, 52, 12, 4

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OFFSET

1,3

COMMENTS

All internal regions in the toothpick structure are squares and rectangles.

LINKS

Table of n, a(n) for n=1..55.

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

FORMULA

T(n,k) = A211008(2^n,k) = 4*A211019(n,k).

T(n,1) = 4*A020988(n-2), n>=2.

EXAMPLE

For n = 5 in the toothpick structure after 2^5 stages we have that:

T(5,1) = 168 is the number of squares of size 1 X 1.

T(5,2) = 212 is the number of rectangles of size 1 X 2.

T(5,3) = 52 is the total number of squares of size 2 X 2 and of rectangles of size 1 X 4.

T(5,4) = 12 is the number of rectangles of size 2 X 4.

T(5,5) = 4 is the number of rectangles of size 2 X 8.

Triangle begins:

0, 4;

8, 12, 4;

40, 52, 12, 4;

168, 212, 52, 12, 4;

680, 852, 212, 52, 12, 4;

2728, 3412, 852, 212, 52, 12, 4;

10920, 13652, 3412, 852, 212, 52, 12, 4;

43688, 54612, 13652, 3412, 852, 212, 52, 12, 4;

174760, 218452, 54612, 13652, 3412, 852, 212, 52, 12, 4;

CROSSREFS

Row sums give 0 together with A145655.

Cf. A020988, A072197, A080675, A139250, A160124, A211008, A211017, A211018, A211019.

Sequence in context: A086480 A260249 A277616 * A103696 A196267 A004469

Adjacent sequences: A211013 A211014 A211015 * A211017 A211018 A211019

KEYWORD

nonn,tabl

AUTHOR

Omar E. Pol, Sep 18 2012

STATUS

approved