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A138963 a(1)=1; a(n+1) = the largest prime divisor of A138793(n+1). 1

%I

%S 1,7,107,149,953,218107,402859,4877,379721,4349353,169373,182473,

%T 1940144339383,2184641,437064932281,5136696159619,67580875919190833,

%U 1156764458711,464994193118899,4617931439293

%N a(1)=1; a(n+1) = the largest prime divisor of A138793(n+1).

%C For the smallest prime divisors of A138793 see A138962.

%H Robert Price, <a href="/A138963/b138963.txt">Table of n, a(n) for n = 1..45</a>

%t b = {}; a = {}; Do[w = RealDigits[n]; w = First[w]; Do[AppendTo[a, w[[k]]], {k, 1, Length[w]}]; p = FromDigits[Reverse[a]]; AppendTo[b, First[Last[FactorInteger[p]]]], {n, 1, 31}]; b (* _Artur Jasinski_, Apr 04 2008 *)

%t lst = {}; Table[First[Last[FactorInteger[FromDigits[Reverse[lst = Join[lst,IntegerDigits[n]]]]]]], {n, 1, 10}] (* _Robert Price_, Mar 22 2015 *)

%Y Cf. A104759, A000422, A116504, A007908, A116505, A104759, A075019, A075020, A075021, A075022, A138789, A138790, A138958, A138959, A138960, A138962.

%K nonn,base

%O 1,2

%A _Artur Jasinski_, Apr 04 2008

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Last modified October 16 13:51 EDT 2019. Contains 328093 sequences. (Running on oeis4.)