|
Search: id:A134487
|
|
|
| A134487 |
|
a(1)=1. For n>=2, a(n) = the largest prime dividing n*a(n-1) + 1. |
|
+0
2
|
|
| 1, 3, 5, 7, 3, 19, 67, 179, 31, 311, 59, 709, 419, 5867, 557, 2971, 61, 157, 373, 829, 1741, 38303, 2381, 1039, 191, 4967, 13411, 375509, 418837, 966547, 14981479, 16127, 16631, 149, 163, 5869, 15511, 829, 137, 29, 17, 13, 7, 103, 61, 401, 31, 1489
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
EXAMPLE
|
a(9)=31 because 9*a(8)+1=9*179+1=1612=2*2*13*31.
|
|
MAPLE
|
with(numtheory): a:=proc(n) local f, L: if n = 1 then 1 else f:=factorset(1+n*a(n-1)): L:=convert(f, list): L[nops(L)] end if end proc: seq(a(n), n=1..35); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 12 2007
|
|
MATHEMATICA
|
a = {1}; Do[AppendTo[a, FactorInteger[(Length[a] + 1)*a[[ -1]] + 1][[ -1, 1]]], {70}]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Oct 30 2007
|
|
CROSSREFS
|
Cf. A134486.
Sequence in context: A130142 A130139 A101088 this_sequence A064537 A023899 A085965
Adjacent sequences: A134484 A134485 A134486 this_sequence A134488 A134489 A134490
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Leroy Quet (qq-quet(AT)mindspring.com), Oct 28 2007
|
|
EXTENSIONS
|
More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Oct 30 2007
|
|
|
Search completed in 0.002 seconds
|
