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Primes of the form floor((Pi/2)^n).
1

%I #20 Jun 25 2017 02:50:50

%S 2,3,23,37,1373,3389,8363,115459401415242179,

%T 45851925215547567394556916118490828192232481476091362012033249370219,

%U 1299908856087615767823951491725300134515972513464867209212961415385730635249

%N Primes of the form floor((Pi/2)^n).

%C The given terms of the sequence correspond to n=2, 3, 7, 8, 16, 18, 20 respectively. There are no other terms for n=21..100000. - _Emeric Deutsch_, Aug 27 2007

%H Vincenzo Librandi, <a href="/A109615/b109615.txt">Table of n, a(n) for n = 1..14</a>

%e A014214(20) = floor((Pi/2)^20) = floor(8363.6825...) = 8363 and 8363 = A000040(1047), therefore 8363 is a term.

%p a:=proc(n) if isprime(floor(((1/2)*Pi)^n))=true then floor(((1/2)*Pi)^n) else end if end proc: seq(a(n),n=1..100); # _Emeric Deutsch_, Aug 27 2007

%t lst={};Do[If[PrimeQ[p=Floor[(Pi/2)^n]],AppendTo[lst,p]],{n,600}

%Y Cf. A014214, A077547.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Aug 01 2005

%E a(8)-a(10) from _Vincenzo Librandi_, Dec 09 2011