1,1

These oscillators work and have the same period in any rule from B3/S5 to B3678/S012567.

NathanielJohnston.com, Rectangular Oscillators in the 2*2 (B36/S125) Cellular Automaton

2x2 at LifeWiki

a(2) = 6 because a 2-by-8 box has period 6 in this rule.

a(n) = 2^(A003558(n) + 1) - 2 for n >= 1

Sequence in context: A091719 A054588 A084106 this_sequence A128660 A145213 A050859

Adjacent sequences: A160654 A160655 A160656 this_sequence A160658 A160659 A160660

nonn

Nathaniel Johnston (nathaniel(AT)nathanieljohnston.com), May 22 2009