A300570 - OEIS

%I #35 Feb 26 2023 10:31:04

%S 1,101,11101,10011101,10110011101,11010110011101,11111010110011101,

%T 100011111010110011101,1001100011111010110011101,

%U 10101001100011111010110011101,101110101001100011111010110011101,1100101110101001100011111010110011101

%N a(n) is the concatenation n in base 2, n-1 in base 2, ..., 1 in base 2.

%H Seiichi Manyama, <a href="/A300570/b300570.txt">Table of n, a(n) for n = 1..155</a>

%H <a href="/index/Mo#MWP">Index entries for sequences related to Most Wanted Primes video</a>

%p a:= proc(n) option remember; `if`(n=1, 1,

%p       parse(cat(convert(n, binary), a(n-1))))

%p     end:

%p seq(a(n), n=1..12);  # _Alois P. Heinz_, Feb 19 2023

%t Table[FromDigits[Flatten[IntegerDigits[#,2]&/@Range[n,1,-1]]],{n,20}] (* _Harvey P. Dale_, Sep 07 2020 *)

%o (Python)

%o from itertools import count, islice

%o def agen(): # generator of terms

%o     s = ""

%o     for k in count(1):

%o         s = bin(k)[2:] + s

%o         yield int(s)

%o print(list(islice(agen(), 15))) # _Michael S. Branicky_, Feb 19 2023

%o (Python)

%o from functools import reduce

%o def A300570(n): return int(bin(reduce(lambda i,j:(i<<j.bit_length())+j,range(n,0,-1)))[2:]) # _Chai Wah Wu_, Feb 26 2023

%Y Cf. A007088, A058935, A300571.

%Y Cf. A098780 (decimal expansion of terms).

%K nonn,base

%O 1,2

%A _Seiichi Manyama_, Mar 08 2018