This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A109615 #28 Jun 08 2025 14:17:34
%S A109615 2,3,23,37,1373,3389,8363,115459401415242179,
%T A109615 45851925215547567394556916118490828192232481476091362012033249370219,
%U A109615 1299908856087615767823951491725300134515972513464867209212961415385730635249
%N A109615 Primes of the form floor((Pi/2)^k).
%C A109615 The given terms of the sequence correspond to k=2, 3, 7, 8, 16, 18, 20 respectively. There are no other terms for k=21..100000. - _Emeric Deutsch_, Aug 27 2007
%H A109615 Vincenzo Librandi, <a href="/A109615/b109615.txt">Table of n, a(n) for n = 1..14</a>.
%e A109615 A014214(20) = floor((Pi/2)^20) = floor(8363.6825...) = 8363 and 8363 = A000040(1047), therefore 8363 is a term.
%p A109615 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 A109615 lst={};Do[If[PrimeQ[p=Floor[(Pi/2)^n]],AppendTo[lst,p]],{n,600}];lst
%Y A109615 Intersection of A000040 and A014214.
%Y A109615 Cf. A077547.
%K A109615 nonn
%O A109615 1,1
%A A109615 _Reinhard Zumkeller_, Aug 01 2005
%E A109615 a(8)-a(10) from _Vincenzo Librandi_, Dec 09 2011