A393109 - OEIS

%I #38 Mar 10 2026 13:34:40

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

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

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

%N Decimal expansion of Product_{p prime} (1 - 1/p^2 + 2/p^3 - 4/p^4 + 2/p^5 + 2/p^6 - 4/p^7 + 2/p^8).

%C The asymptotic probability that the greatest common bi-unitary divisor of two positive integers selected independently at random is 1.

%e 0.703144419850627757322097009886130216782385175212355...

%o (PARI) prodeulerrat(1 - 1/p^2 + 2/p^3 - 4/p^4 + 2/p^5 + 2/p^6 - 4/p^7 + 2/p^8)

%Y Cf. A222266.

%Y Analogous constants: A059956, A306071, A393948.

%K nonn,cons

%O 0,1

%A _Amiram Eldar_, Mar 10 2026