A028910 Arrange digits of 2^n in descending order.

1, 2, 4, 8, 61, 32, 64, 821, 652, 521, 4210, 8420, 9640, 9821, 86431, 87632, 66553, 732110, 644221, 885422, 8765410, 9752210, 9444310, 8888630, 77766211, 55443332, 88766410, 877432211, 866554432, 987653210, 8774432110, 8876444321

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• base

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..3321

Crossrefs

The following are parallel families: A000079 (2^n), A004094 (2^n reversed), A028909 (2^n sorted up), A028910 (2^n sorted down), A036447 (double and reverse), A057615 (double and sort up), A263451 (double and sort down); A000244 (3^n), A004167 (3^n reversed), A321540 (3^n sorted up), A321539 (3^n sorted down), A163632 (triple and reverse), A321542 (triple and sort up), A321541 (triple and sort down).

Programs

Magma

[Seqint(Sort(Intseq(2^n))):n in [0..31]]; // Marius A. Burtea, Oct 06 2019

Maple

a:= n-> parse(cat(sort(convert(2^n, base, 10), `>`)[])):
seq(a(n), n=0..50);  # Alois P. Heinz, Jan 21 2020

Mathematica

FromDigits[Reverse[Sort[IntegerDigits[#]]]]&/@(2^Range[0,40]) (* Harvey P. Dale, Mar 06 2020 *)

Python

def A028910(n):
    return int(''.join(sorted(str(2**n),reverse=True))) # Chai Wah Wu, Feb 19 2021

Extensions

More terms from Patrick De Geest, Apr 15 1998