A028909 Arrange digits of 2^n in ascending order.
1, 2, 4, 8, 16, 23, 46, 128, 256, 125, 124, 248, 469, 1289, 13468, 23678, 35566, 11237, 122446, 224588, 145678, 122579, 134449, 368888, 11266777, 23334455, 1466788, 112234778, 234455668, 12356789, 112344778, 1234446788, 2244667999
Offset: 0
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..3600
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
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Magma
[Seqint(Reverse(Sort(Intseq(2^n)))):n in [0..35]]; // Vincenzo Librandi, Jan 22 2020
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Maple
a:= n-> parse(cat(sort(convert(2^n, base, 10))[])): seq(a(n), n=0..50); # Alois P. Heinz, Jan 21 2020
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Mathematica
Table[FromDigits[Sort[IntegerDigits[2^n]]],{n,0,40}] (* Harvey P. Dale, Aug 20 2013 *) -
Python
def A028909(n): return int(''.join(sorted(str(2**n)))) # Chai Wah Wu, Feb 19 2021
Extensions
More terms from Patrick De Geest, Apr 1998
Comments