A216706 - OEIS

%I #15 Jan 03 2021 13:15:36

%S 1,90,8550,826500,80583750,7897207500,776558737500,76546504125000,

%T 7558967282343750,747497875698437500,74002289694145312500,

%U 7332954160601671875000,727184620926332460937500,72159089307305298046875000,7164366724082454591796875000

%N a(n) = Product_{k=1..n} (100 - 10/k).

%C This sequence is generalizable: Product_{k=1..n} (q^2 - q/k) = (q^n/n!) * Product_{k=0..n-1} (q*k + q-1) = expansion of (1- x*q^2)^((1-q)/q).

%p seq(product(100-10/k, k=1.. n), n=0..20);

%p seq((10^n/n!)*product(10*k+9, k=0.. n-1), n=0..20);

%Y Cf. A004988, A049382, A004994, A216702, A216703, A216704, A216705.

%K nonn

%O 0,2

%A _Michel Lagneau_, Sep 16 2012