A170926 Total number of squares and rectangles at the n-th stage in the corner toothpick structure (see A152890, A153006).

0, 0, 1, 3, 4, 5, 10, 17, 20, 21, 25, 30, 33, 40, 58, 77, 84, 85, 89, 94, 97, 104, 121, 138, 145, 151, 164, 177, 190, 222, 278, 325, 340, 341, 345, 350, 353, 360, 377, 394, 401, 407, 420, 433, 446, 478, 533, 578, 593, 599, 612, 625, 638, 669, 720, 761, 781, 806, 845, 884, 942

Offset: 0

Author

Omar E. Pol, Jan 18 2010

Keywords

• nonn

Links

• David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4*3^(wt(n-1)-1) for n >= 2.]
• N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Crossrefs

Partial sums of A168131.

Formula

a(2^k) = (4^k-4)/3 for k >= 2. - N. J. A. Sloane, Feb 13 2010.

Extensions

Edited and extended by N. J. A. Sloane, Feb 01 2010