A089650 a(n) = A089649(n) mod 3.

1, 2, 0, 1, 0, 2, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 0, 2, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 0, 2, 1, 1, 1, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 1, 1, 1, 0, 2, 1, 2, 0, 1, 0, 2, 1, 1, 1, 1, 2, 0, 1, 0, 2, 1, 1, 1, 1, 2, 0, 1, 0, 2, 1, 1, 1, 1, 2, 0, 1, 0, 2, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 0, 2, 1, 2, 0, 1, 2, 0

Offset: 1

Author

Philippe Deléham, Jan 02 2004

Keywords

• easy
• nonn

Comments

Partial sums, modulo 3, of the sequence: a(1)=1, a(1), a(1), a(1), a(2), a(2), a(2), a(3), a(3), ... each term repeated 3 times.

Links

• Index entries for sequences that are fixed points of mappings

Programs

Mathematica

Nest[ Function[ l, {Flatten[(l /. {0 -> {1, 1, 1}, 1 -> {1, 2, 0}, 2 -> {1, 0, 2}})]}], {0}, 5] (* Robert G. Wilson v, Feb 26 2005 *)

PARI

a(n)=if(n<2,1,(a(n-1)+a(floor((n+1)/3)))%3)

Formula

A fixed point of the morphism 1->120, 2->102, 0->111.