A257345 Regard the terms of A004290 as binary numbers and convert to base 10.

0, 1, 2, 7, 4, 2, 14, 9, 8, 511, 2, 3, 28, 9, 18, 14, 16, 29, 1022, 25, 4, 21, 6, 53, 56, 4, 18, 895, 36, 109, 14, 59, 32, 63, 58, 18, 2044, 7, 50, 21, 8, 31, 42, 109, 12, 1022, 106, 19, 112, 97, 4, 35, 36, 35, 1790, 6, 72, 25, 218, 223, 28, 37, 118, 991, 64

Offset: 0

Author

N. J. A. Sloane, Apr 29 2015

Keywords

• nonn
• base

Comments

Of course the terms of A004290 are already in base 10 (they just happen to involve only the digits 0 and 1), so there is no justification for this sequence other than curiosity.

a(n) < 2^n. - Chai Wah Wu, Apr 29 2015

Links

• Chai Wah Wu, Table of n, a(n) for n = 0..9998

Crossrefs

Cf. A079339, A004290, A131577.

Programs

Mathematica

s = With[{c = Rest[Union[FromDigits /@ Flatten[Table[Tuples[{1, 0}, i], {i, 10}], 1]]]}, Join[{0}, Flatten[Table[Select[c, Divisible[#, n] &, 1], {n, 120}]]]]; FromDigits[IntegerDigits@ #, 2] & /@ s (* Michael De Vlieger, Apr 29 2015, after Harvey P. Dale at A004290 *)

Python

def A257345(n):
    if n > 0:
        for i in range(1, 2**n):
            x = int(format(i, 'b'))
            if not x % n:
                return int(str(x), 2)
    return 0 # Chai Wah Wu, Apr 29 2015

Extensions

More terms from Chai Wah Wu, Apr 29 2015