OFFSET
1,1
EXAMPLE
a(3) is 25 because the third composite is 8, the eighth composite is 15, and for the 3rd iteration, the fifteenth composite is 25.
To get a(4): 4 -> 9 -> 16 -> 26 -> 39.
MATHEMATICA
c = Select[Range[10^6], CompositeQ]; Table[Nest[c[[#]] &, n, n], {n, 50}] (* Michael De Vlieger, Dec 31 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Matthew Campbell, Dec 31 2016
EXTENSIONS
More terms from Michael De Vlieger, Dec 31 2016
STATUS
approved