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A076672 Smallest a(n)>a(n-1) such that a(n)^2+a(n-1)^2 is a perfect square, a(1)=6. 0

%I #13 Mar 12 2014 00:53:07

%S 6,8,15,20,21,28,45,60,63,84,112,180,189,252,275,660,693,924,1232,

%T 1326,1768,1974,2632,4026,5368,6405,8200,8319,11092,11715,15620,16401,

%U 19720,20706,20880,20910,24752,24960,25300,26565,29716

%N Smallest a(n)>a(n-1) such that a(n)^2+a(n-1)^2 is a perfect square, a(1)=6.

%C The sequence is infinite.

%t Clear[nxt]; nxt[n_]:=Module[{i=n+1},While[!IntegerQ[Sqrt[n^2+i^2]],i++]; i]; NestList[nxt,6,40] (* _Harvey P. Dale_, Dec 03 2010 *)

%Y Cf. A076600, A076671 (starting at 5).

%K nonn

%O 1,1

%A _Zak Seidov_, Oct 25 2002

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Last modified April 23 03:30 EDT 2024. Contains 371906 sequences. (Running on oeis4.)