A394043 - OEIS

%I #5 Mar 08 2026 10:27:19

%S 9,8,9,0,3,6,4,7,2,4,5,1,7,3,6,5,9,1,4,0,8,6,5,0,5,6,1,3,3,4,4,6,5,9,

%T 5,6,4,8,3,9,3,6,4,4,3,3,9,9,1,2,4,3,8,7,8,3,9,6,7,6,1,5,0,1,0,1,0,5,

%U 0,2,8,8,0,8,0,2,0,9,9,9,6,1,4,9,1,2,6,7,4,5,4,6,6,8,4,1,6,9,4,7,0,6,8,8,7

%N Decimal expansion of Product_{p prime} (1 - 1/(p^2*(p^2+p-1)^2)).

%C The asymptotic probability that the greatest common divisor of two exponentially odd numbers (A268335) selected independently at random is a squarefree number (A005117).

%F Equals A394044 / A065463^2.

%e 0.989036472451736591408650561334465956483936443399124...

%o (PARI) prodeulerrat(1 - 1/(p^2*(p^2+p-1)^2))

%Y Cf. A005117, A065463, A268335, A394041, A394044.

%K nonn,cons

%O 0,1

%A _Amiram Eldar_, Mar 08 2026