A161334 Numbers of snowflake sequence, divided by 2: a(n) = A161330(n)/2.

0, 1, 4, 7, 10, 19, 22, 31, 40, 49, 64, 73, 88, 109, 112, 121, 130, 145, 172, 187, 226, 247, 274, 313, 334, 367, 406, 415, 436, 457, 484, 529, 562, 625, 670, 715, 766, 799, 838, 883, 928, 973, 1000, 1033, 1090, 1129, 1192, 1255, 1306, 1357, 1426, 1477

Offset: 0

Author

Omar E. Pol, Jun 07 2009

Keywords

• nonn

Comments

Also number of E-toothpicks after n-th stage on the semi-infinite triangular grid. A161332 (the first differences) gives the number of E-toothpicks added at n-th stage. - Omar E. Pol, Jan 07 2014

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, A single E-toothpick
• N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Crossrefs

Cf. A139250, A161328, A161330, A161331, A161332, A161333.

Extensions

More terms from Omar E. Pol, Jan 07 2014