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A076602 a(1)=7, a(n_even)=(a(n-1)^2-1)/2; a(n_odd)=a(n-1)+1. 1

%I

%S 7,24,25,312,313,48984,48985,1199765112,1199765113,719718163185951384,

%T 719718163185951385,258997117209879873736794713791709112,

%U 258997117209879873736794713791709113,33539753361514126736178628392779244498735703225085922505721228803623384

%N a(1)=7, a(n_even)=(a(n-1)^2-1)/2; a(n_odd)=a(n-1)+1.

%C {7, 24, 25}, {25, 312, 313}, {313, 48984, 48985}... are sides {a<b<c} of the right triangles, with hypotenuse c=b+1.

%t nxt[{a_,b_}]:={a+1,If[OddQ[a],(b^2-1)/2,b+1]}; Transpose[NestList[nxt,{1,7},15]][[2]] (* _Harvey P. Dale_, Dec 13 2011 *)

%K easy,nonn

%O 1,1

%A _Zak Seidov_, Oct 21 2002

%E More terms from _Harvey P. Dale_, Dec 13 2011

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Last modified January 22 11:09 EST 2022. Contains 350481 sequences. (Running on oeis4.)