A220520 Number of toothpicks and D-toothpicks after n-th stage in the D-toothpick "wide" triangle of the third kind.

0, 1, 3, 7, 11, 15, 19, 27, 35, 39, 43, 51, 63, 79, 91, 107, 123, 127, 131, 139, 151, 167, 187, 211, 237, 261, 273, 293, 325, 365, 393, 425, 457, 461, 465, 473, 485, 501, 521, 545, 571, 595, 615, 647, 691, 755, 807, 855, 909, 944, 961, 981, 1017, 1065

Offset: 0

Author

Omar E. Pol, Dec 15 2012

Keywords

• nonn

Comments

The structure is essentially one of the vertical wedges of several D-toothpick structures. For more information see A220500. First differs from A194440 at a(14). The first differences (A220521) give the number of toothpicks or D-toothpicks added at n-th stage. See A220522 for the "narrow" triangle of the third kind.

Links

• Omar E. Pol, Illustration of the structure after 32 stages
• Omar E. Pol, Illustration of the structure after 64 stages
• N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS
• Index entries for sequences related to toothpick sequences

Crossrefs

Cf. A047999, A139250, A194270, A194440, A194442, A220494, A220521, A220522.