OFFSET
1,6
FORMULA
a(1)=0, a(2)=1, a(n): if n mod 3 is 0: a(n)=a(n-2) + a(n-1), if n mod 3 is 1: a(n)=a(n-2) * a(n-1), if n mod 3 is 2: a(n)=a(n-2)^a(n-1).
EXAMPLE
a(11) = a(9)^a(10)=6^24 because 11 mod 3 is 2.
MATHEMATICA
nxt[{n_, a_, b_}]:={n+1, b, Which[Mod[n+1, 3]==0, a+b, Mod[n+1, 3]==1, a*b, True, a^b]}; NestList[ nxt, {2, 0, 1}, 12][[;; , 2]] (* Harvey P. Dale, Oct 04 2023 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Anthony Peterson (civ2buf(AT)ricochet.com), Jul 09 2003
EXTENSIONS
The next 2 terms are (6^24)^((6^24)*(6^24+24)) and (6^24)^((6^24) * (6^24 + 24)) + (6^24) * (6^24 + 24).
STATUS
approved