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A113892
a(1) = 3; thereafter, a(n+1) is the largest prime divisor of the concatenation of all previous terms.
0
3, 3, 11, 43, 151, 2837, 55582381, 55582381, 604182026353013, 7260821549599941816463, 10950115817553553947281369915579, 10950115817553553947281369915579
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
Cf. A095215.
Sequence in context: A376024 A176956 A200861 * A334283 A365110 A350921
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