OFFSET
-1,3
COMMENTS
See A054871 for definitions and key links.
EXAMPLE
a(-1)= H_5(3,-1)= 0;
a(0) = H_5(3,0) = 1;
a(1) = H_5(3,1) = 3;
a(2) = H_5(3,2) = H_4(3, H_4(3,1)) = H_4(3,3) = 3^3^3 = 7625597484987;
MATHEMATICA
NestList[3^#^3 &, 0, 3] (* Vincenzo Librandi, Jan 18 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Natan Arie Consigli, Jan 12 2016
STATUS
approved