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%I #16 Nov 20 2018 19:28:10
%S 3,31,47,113,659,1021,1187,1979,2971,3251,5749,9679,10433,14627,20593,
%T 22807,23957,35107,39461,55813,58207,109063,152417,157349,201881,
%U 227419,244463,262121,292469,295187,310357,318793,320209,323053,328777,333103
%N Primes of the form floor(k*(k+1)*Pi/2), k>=0, where Pi = 3.1415.. = A000796.
%H G. C. Greubel, <a href="/A163579/b163579.txt">Table of n, a(n) for n = 1..1000</a>
%t s=0;lst={};Do[s+=n;p=IntegerPart[s];If[PrimeQ[p],AppendTo[lst,p]],{n,0,7!,Pi}];lst
%t Select[Floor[Accumulate[Range[800]]*Pi],PrimeQ] (* _Harvey P. Dale_, Nov 20 2018 *)
%o (PARI) for(n=1,500, m=floor(n*(n+1)*Pi/2); if(isprime(m), print1(m, ", "))) \\ _G. C. Greubel_, Jul 28 2017
%K nonn
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, Jul 31 2009
%E Definition clarified by _R. J. Mathar_, Sep 24 2011
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