A299476 Toothpick sequence on triangular grid with word "abcb".

0, 1, 3, 7, 13, 21, 27, 39, 49, 57, 69, 87, 111, 135, 155, 185, 203, 211, 223, 241, 265, 293, 321, 367, 405, 453, 499, 567, 633, 701, 751, 823, 859, 869, 881, 899, 923, 951, 979, 1025, 1067, 1119, 1179, 1259, 1347, 1439, 1529, 1647, 1731, 1805

Offset: 0

Author

Omar E. Pol, Feb 11 2018

Keywords

• nonn
• more

Comments

a(n) gives the number of toothpicks of length 2 in the structure after n-th stage.

A299477 (the first differences) gives the number of toothpicks added at n-th stage.

For more information about the "word" of a cellular automaton see A296612.

Links

• 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

Cf. A299477 (first differences), A296612.

Cf. A160120 (word "a"), A139250 (word "ab"), A296510 (word "abc"), A299478 (word "abcbc").