OFFSET
1,1
EXAMPLE
The largest prime divisor of 3311 is 43. 3311 = 7*11*43. Hence a(4) = 43.
MATHEMATICA
a[1] = 3; a[n_] := a[n] = FactorInteger[ FromDigits@ Flatten[ IntegerDigits /@ Array[a, n - 1]]][[ -1, 1]]; Array[a, 12] (* Robert G. Wilson v, Aug 31 2008 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 18 2005
EXTENSIONS
More terms from Stefan Steinerberger, Nov 19 2005
2 more terms from Robert G. Wilson v, Aug 31 2008
STATUS
approved