Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #18 Apr 01 2023 12:08:56
%S 0,1,1011,1101111,10001010111,10101101100111,11011001000000111,
%T 100001111010001000111,101010011000101011000111,
%U 110100111110110101111000111,1000010001110100011010111000111,1010010110010001100001100111000111,1100111011110101111010000000111000111
%N Decimal repunits written in base 2.
%C Interpreting A002275 as binary numbers and converting to decimal gives A000225. This sequence gives the resulting terms of the "reverse" operation.
%C The n least significant bits of a(n) seem to converge to A088911 as n increases.
%H Seiichi Manyama, <a href="/A291962/b291962.txt">Table of n, a(n) for n = 0..301</a>
%F a(n) = A007088(A002275(n)).
%t Table[FromDigits@ IntegerDigits[Floor[10^n/9], 2], {n, 0, 12}] (* _Michael De Vlieger_, Sep 06 2017 *)
%t FromDigits[IntegerDigits[#,2]]&/@Table[FromDigits[PadRight[{},n,1]],{n,0,20}] (* _Harvey P. Dale_, Apr 01 2023 *)
%o (PARI) a(n) = subst(Pol(binary((10^n-1)/9)), x, 10)
%o (Python)
%o def a(n): return 0 if n == 0 else int(bin(int("1"*n))[2:])
%o print([a(n) for n in range(13)]) # _Michael S. Branicky_, Apr 26 2022
%Y Cf. A000225, A002275, A007088, A088911.
%K nonn,base,easy
%O 0,3
%A _Felix Fröhlich_, Sep 06 2017