A151779 a(1)=1; for n > 1, a(n)=6*5^{wt(n-1)-1}.

1, 6, 6, 30, 6, 30, 30, 150, 6, 30, 30, 150, 30, 150, 150, 750, 6, 30, 30, 150, 30, 150, 150, 750, 30, 150, 150, 750, 150, 750, 750, 3750, 6, 30, 30, 150, 30, 150, 150, 750, 30, 150, 150, 750, 150, 750, 750, 3750, 30, 150, 150, 750, 150, 750, 750, 3750, 150, 750, 750, 3750

Offset

1,2

Comments

Number of cells turned ON in n-th generation of cellular automaton based on Z^3 lattice in the same way that A147562 is based on the Z^2 lattice. Here each cell has six neighbors.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

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

Maple

wt := proc(n) local w, m, i; w := 0; m := n; while m > 0 do i := m mod 2; w := w+i; m := (m-i)/2; od; w; end:
f:=d->[seq((2*d)*(2*d-1)^(wt(n-1)-1), n=2..120)];
f2:=d->[1, op(f(d))];
f2(3);

Prog

(PARI) a(n)=6*5^(hammingweight(n-1)-1)\1 \\ Charles R Greathouse IV, Mar 07 2015

Crossrefs

Cf. A147582, A151780, A151781, A151782.

Sequence in context: A253066 A267651 A016725 * A255462 A066714 A054436

Adjacent sequences: A151776 A151777 A151778 * A151780 A151781 A151782

Keyword

nonn,easy

Author

N. J. A. Sloane, Jun 25 2009

Status

approved