A242347 Number of decimal digits of A008559.

1, 2, 4, 10, 31, 100, 330, 1093, 3628, 12049, 40023, 132951, 441651, 1467130, 4873698, 16190071, 53782249, 178660761, 593498199, 1971558339

Offset: 1

Author

J. Lowell, May 11 2014

Keywords

• nonn
• base
• more

Comments

a(n+1)/a(n) is approximately log_2(10) = A020862. - André Engels, Apr 01 2021

Examples

			a(3) = 4 because 1010 has 4 decimal digits.
		

Links

• Code Golf StackExchange, Length of Binary as Base 10 [OEIS A242347], coding challenge started Oct 28 2022.

Crossrefs

Cf. A008559, A055642, A020862.

Programs

PARI

a242347(n) = {my (k=2, d=digits); while(n--, k=fromdigits(d(k,2))); #d(k)} \\ Hugo Pfoertner, Nov 04 2022

Python

A242347_list, l = [1], 2
for _ in range(10):
    l = int(bin(l)[2:])
    A242347_list.append(len(str(l))) # Chai Wah Wu, Dec 26 2014

Formula

a(n) = A055642(A008559(n)). - Michel Marcus, May 11 2014

Extensions

a(1), a(18)-a(20) from Chai Wah Wu, Dec 26 2014