A394044 Decimal expansion of Product_{p prime} (1 - 2/p^2 + 2/p^3 - 1/p^4).

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

Offset

0,1

Comments

The asymptotic probability that two positive integers selected independently at random are both exponentially odd numbers numbers (A268335), and their greatest common divisor is a squarefree number (A005117).

Links

Table of n, a(n) for n=0..104.

Formula

Equals A065463^2 * A394043.

Example

0.490798286634728225909154323920711804307234495196201...

Prog

(PARI) prodeulerrat(1 - 2/p^2 + 2/p^3 - 1/p^4)

Crossrefs

Cf. A005117, A065463, A268335, A394042, A394043.

Sequence in context: A020802 A085675 A254133 * A303984 A336308 A070439

Adjacent sequences: A394041 A394042 A394043 * A394045 A394046 A394047

Keyword

nonn,cons

Author

Amiram Eldar, Mar 08 2026

Status

approved