The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A076560 a(1)=1; a(n>1)= greatest prime divisor of (a(n-1) + n). 3

%I #12 Jun 21 2023 04:02:01

%S 1,3,3,7,3,3,5,13,11,7,3,5,3,17,2,3,5,23,7,3,3,5,7,31,7,11,19,47,19,7,

%T 19,17,5,13,3,13,5,43,41,3,11,53,3,47,23,23,7,11,5,11,31,83,17,71,7,7,

%U 2,5,2,31,23,17,5,23,11,11,13,3,3,73,3,5,13,29,13,89,83,23,17,97,89,19

%N a(1)=1; a(n>1)= greatest prime divisor of (a(n-1) + n).

%H Harvey P. Dale, <a href="/A076560/b076560.txt">Table of n, a(n) for n = 1..1000</a>

%t nxt[{n_,a_}]:={n+1,FactorInteger[a+n+1][[-1,1]]}; Transpose[NestList[nxt,{1,1},90]][[2]] (* _Harvey P. Dale_, Nov 29 2013 *)

%o (PARI) gpf(n) = if(n==1,1, my(v=factor(n)[,1]); v[#v]);

%o a_vector(len) = my(t=0); vector(len,n, t=gpf(t+n)); \\ _Kevin Ryde_, Jun 21 2023

%Y Cf. A006530 (gpf), A362138.

%K easy,nonn

%O 1,2

%A _Zak Seidov_, Oct 19 2002

%E Definition clarified by _Harvey P. Dale_, Nov 29 2013

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 16 08:41 EDT 2024. Contains 372552 sequences. (Running on oeis4.)