OFFSET
0,9
LINKS
Eric Weisstein's World of Mathematics, Power Tower
Wikipedia, Knuth's up-arrow notation
Wikipedia, Tetration
EXAMPLE
Square array A(n,k) begins:
1, 0, 1, 0, 1, 0, 1, ...
1, 1, 1, 1, 1, 1, 1, ...
1, 2, 4, 16, 65536, ...
1, 3, 27, 7625597484987, ...
1, 4, 256, ...
1, 5, 3125, ...
1, 6, 46656, ...
1, 7, 823543, ...
...
MAPLE
A:= (n, k)-> `if`(k=0, 1, n^A(n, k-1)):
seq(seq(A(n, d-n), n=0..d), d=0..6);
CROSSREFS
Main diagonal gives A004231 (Ackermann's sequence).
KEYWORD
nonn,tabl
AUTHOR
Alois P. Heinz, Nov 03 2018
STATUS
approved