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!)
A076601 a(1)=3, a(n_even)=(a(n-1)^2-1)/2; a(n_odd)=a(n-1)+1. 1

%I #10 May 11 2018 01:42:03

%S 3,4,5,12,13,84,85,3612,3613,6526884,6526885,21300113901612,

%T 21300113901613,226847426110843688722000884,

%U 226847426110843688722000885,25729877366557343481074291996721923093306518970391612,25729877366557343481074291996721923093306518970391613

%N a(1)=3, a(n_even)=(a(n-1)^2-1)/2; a(n_odd)=a(n-1)+1.

%C {3, 4, 5}, {5, 12, 13}, {13, 84, 85}... are sides {a<b<c} of the right triangles, with hypotenuse c=b+1.

%t Transpose[NestList[{#[[1]]+1,If[EvenQ[#[[1]]+1],(#[[2]]^2-1)/2,#[[2]]+1]}&,{1,3},20]][[2]] (* _Harvey P. Dale_, May 02 2012 *)

%K easy,nonn

%O 1,1

%A _Zak Seidov_, Oct 21 2002

%E More terms from _Harvey P. Dale_, May 02 2012

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 June 7 14:21 EDT 2024. Contains 373195 sequences. (Running on oeis4.)