A113892 a(1) = 3; thereafter, a(n+1) is the largest prime divisor of the concatenation of all previous terms.

3, 3, 11, 43, 151, 2837, 55582381, 55582381, 604182026353013, 7260821549599941816463, 10950115817553553947281369915579, 10950115817553553947281369915579

Offset

1,1

Links

Table of n, a(n) for n=1..12.

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

Adjacent sequences: A113889 A113890 A113891 * A113893 A113894 A113895

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