A291962 Decimal repunits written in base 2.

0, 1, 1011, 1101111, 10001010111, 10101101100111, 11011001000000111, 100001111010001000111, 101010011000101011000111, 110100111110110101111000111, 1000010001110100011010111000111, 1010010110010001100001100111000111, 1100111011110101111010000000111000111

Offset: 0

Author

Felix Fröhlich, Sep 06 2017

Keywords

• nonn
• base
• easy

Comments

Interpreting A002275 as binary numbers and converting to decimal gives A000225. This sequence gives the resulting terms of the "reverse" operation.

The n least significant bits of a(n) seem to converge to A088911 as n increases.

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..301

Crossrefs

Cf. A000225, A002275, A007088, A088911.

Programs

Mathematica

Table[FromDigits@ IntegerDigits[Floor[10^n/9], 2], {n, 0, 12}] (* Michael De Vlieger, Sep 06 2017 *)
FromDigits[IntegerDigits[#,2]]&/@Table[FromDigits[PadRight[{},n,1]],{n,0,20}] (* Harvey P. Dale, Apr 01 2023 *)

PARI

a(n) = subst(Pol(binary((10^n-1)/9)), x, 10)

Python

def a(n): return 0 if n == 0 else int(bin(int("1"*n))[2:])
print([a(n) for n in range(13)]) # Michael S. Branicky, Apr 26 2022

Formula

a(n) = A007088(A002275(n)).