A151914 a(0)=0, a(1)=4; for n>=2, a(n) = (8/3)*(Sum_{i=1..n-1} 3^wt(i)) + 4, where wt() = A000120().

0, 4, 12, 20, 44, 52, 76, 100, 172, 180, 204, 228, 300, 324, 396, 468, 684, 692, 716, 740, 812, 836, 908, 980, 1196, 1220, 1292, 1364, 1580, 1652, 1868, 2084, 2732, 2740, 2764, 2788, 2860, 2884, 2956, 3028, 3244, 3268, 3340, 3412, 3628, 3700, 3916, 4132, 4780

Offset: 0

Author

N. J. A. Sloane, Aug 05 2009, Aug 06 2009

Keywords

• nonn
• easy

Comments

Also, total number of "ON" "subcells" at n-th stage in two of the four wedges of the "Ulam-Warburton" two-dimensional cellular automaton of A147562, but including the central "ON" cell. Assume that every "ON" cell contains four "subcells". - Omar E. Pol, Feb 22 2015

Links

• N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS
• Index entries for sequences related to cellular automata

Crossrefs

Cf. A079315, A079317, A147562, A151917, A151920.

Formula

a(n) = A079315(2n).

For n>=2, a(n) = 8*A151920(n-2) + 4.

a(n) = 4*A151917(n). - Omar E. Pol, Feb 22 2015