login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A138963 a(1)=1; a(n+1) = the biggest prime divisor of A138793(n+1). 0
1, 7, 107, 149, 953, 218107, 402859, 4877, 379721, 4349353, 169373, 182473, 1940144339383, 2184641, 437064932281, 5136696159619, 67580875919190833, 1156764458711, 464994193118899, 4617931439293 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

For the smallest prime divisors of A138793 see A138962

MATHEMATICA

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*)

CROSSREFS

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

Sequence in context: A141362 A188407 A075021 * A141932 A002687 A166547

Adjacent sequences:  A138960 A138961 A138962 * A138964 A138965 A138966

KEYWORD

nonn

AUTHOR

Artur Jasinski (grafix(AT)csl.pl), Apr 04 2008

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 16 06:05 EST 2012. Contains 205860 sequences.