A390696 a(n) = floor(n * log_10(2^64)).

0, 19, 38, 57, 77, 96, 115, 134, 154, 173, 192, 211, 231, 250, 269, 288, 308, 327, 346, 366, 385, 404, 423, 443, 462, 481, 500, 520, 539, 558, 577, 597, 616, 635, 655, 674, 693, 712, 732, 751, 770, 789, 809, 828, 847, 866, 886, 905, 924, 944, 963, 982, 1001

Offset

0,2

Comments

It takes n words of 64 bits, to represent the unsigned value 10^a(n)-1.

Links

Paolo Xausa, Table of n, a(n) for n = 0..10000

Formula

a(n) = floor(n * log_10(2^64)).

Mathematica

Floor[Range[0, 55]*Log10[2^64]] (* Paolo Xausa, Nov 23 2025 *)

Prog

(PARI) a(n) = logint(2^(64*n), 10)
(Python)
def A390696(n): return len(str(1<<(n<<6)))-1 # Chai Wah Wu, Nov 24 2025

Crossrefs

Sequence in context: A235030 A048844 A008601 * A033900 A110288 A318260

Adjacent sequences: A390693 A390694 A390695 * A390697 A390698 A390699

Keyword

nonn,easy

Author

Ruud H.G. van Tol, Nov 15 2025

Status

approved