%I #24 Aug 24 2019 22:19:58
%S 0,6,25,90,295,945,2995,9450,29749,93555,294058,924041,2903320,
%T 9121612,28657269,90030844,282842403,888579011,2791558622,8769948429,
%U 27551618702,86555983552,271923674474,854273468992,2683779334331,8431341566236,26487840921750,83214006759229,261424512797515
%N a(n) = floor(Pi^n/Zeta(n)).
%H <a href="/index/Z#zeta_function">Index entries for zeta function</a>.
%F a(2*n) = A100594(n).
%e Pi^12/Zeta(12) = 638512875/691 = 924041.78... So a(12) = 924041.
%t Table[Floor[Pi^n/Zeta[n]], {n, 20}] (* _Alonso del Arte_, Aug 24 2019 *)
%o (PARI) {a(n) = if(n==1, 0, n==4, 90, floor(Pi^n/zeta(n)))}
%Y Decimal expansion of Pi^k/Zeta(k): A308637 (k = 3), A309926 (k = 5), A309927 (k = 7), A309928 (k = 9), A309929 (k = 11).
%Y Cf. A001672 (floor(Pi^n)), A002432, A046988, A100594.
%K nonn
%O 1,2
%A _Seiichi Manyama_, Aug 24 2019