A375246 Number of biquadratefree numbers <= 10^n.

1, 10, 93, 925, 9240, 92395, 923939, 9239385, 92393839, 923938406, 9239384029, 92393840300, 923938402926, 9239384029211, 92393840292169, 923938402921591, 9239384029215891, 92393840292159004, 923938402921590127, 9239384029215901651, 92393840292159016603

Offset: 0

Author

Chai Wah Wu, Aug 07 2024

Keywords

• nonn

Comments

Digits of terms converge to digits of 1/zeta(4) = 90/Pi^4 (A215267).

Links

• Chai Wah Wu, Table of n, a(n) for n = 0..39

Crossrefs

Cf. A060431, A013662, A046100, A215267, A307430, A375245.

Programs

Python

from sympy import mobius, integer_nthroot
def A375246(n): return int(sum(mobius(k)*(10**n//k**4) for k in range(1, integer_nthroot(10**n,4)[0]+1)))

Formula

a(n) = A375245(10^n).