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 A155174 Long leg B of primitive Pythagorean triangles such that perimeters are Averages of twin prime pairs, q=p+1, a=q^2-p^2, c=q^2+p^2, b=2*p*q, s=a+b+c, s-+1 are primes.*) 8

%I

%S 4,12,112,220,840,1740,3960,5100,8580,9940,11704,12012,20604,21840,

%T 23112,26680,47740,61600,78012,82012,102604,103512,122512,151800,

%U 276024,289560,340312,418612,481180,501000,660100,711624,838512,901824,931612

%N Long leg B of primitive Pythagorean triangles such that perimeters are Averages of twin prime pairs, q=p+1, a=q^2-p^2, c=q^2+p^2, b=2*p*q, s=a+b+c, s-+1 are primes.*)

%C p=1,q=2,a=3,b=4,c=5,s=12-+1 primes, ...

%t lst={};Do[p=n;q=p+1;a=q^2-p^2;c=q^2+p^2;b=2*p*q;s=a+b+c;If[PrimeQ[s-1]&&PrimeQ[s+1],AppendTo[lst,b]],{n,8!}];lst

%Y Cf. A020882, A020886, A020884, A020883, A024364, A024406, A155171, A155173

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jan 21 2009

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Last modified October 20 11:18 EDT 2019. Contains 328257 sequences. (Running on oeis4.)