A081431 RevBinary(RevDecimal(n)), where RevBinary(m) is the binary reversal of m (A030101) and RevDecimal(m) is the decimal reversal of m (A004086).

0, 1, 1, 3, 1, 5, 3, 7, 1, 9, 1, 13, 21, 31, 37, 51, 47, 113, 69, 109, 1, 3, 13, 1, 21, 11, 31, 9, 37, 29, 3, 11, 29, 33, 53, 43, 63, 73, 101, 93, 1, 7, 3, 17, 13, 27, 1, 41, 21, 61, 5, 15, 19, 49, 45, 59, 65, 105, 85, 125, 3, 1, 11, 9, 29, 7, 33, 25, 53, 3, 7, 17, 27, 41

Offset: 0

Author

Reinhard Zumkeller, Mar 20 2003

Keywords

• nonn
• base

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A004086, A030101.

Cf. A081432, A081433, A007088.

Programs

Mathematica

Table[IntegerReverse[IntegerReverse[n],2],{n,0,80}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 03 2018 *)

PARI

a(n) = fromdigits(Vecrev(binary(fromdigits(Vecrev(digits(n))))), 2); \\ Michel Marcus, Jan 30 2023

Python

def a(n): return int(bin(int(str(n)[::-1]))[:1:-1], 2)
print([a(n) for n in range(74)]) # Michael S. Branicky, Jan 30 2023

Formula

a(n) = A030101(A004086(n)). - Michel Marcus, Jan 30 2023