A306392 a(n) = 2^n with 1's and 2's swapped.

2, 1, 4, 8, 26, 31, 64, 218, 156, 521, 2014, 1048, 4096, 8291, 26384, 31768, 65536, 232071, 161244, 514188, 2048576, 1097251, 4294304, 8388608, 26777126, 33554431, 67208864, 234127718, 168435456, 536870921, 2073742814, 1247483648, 4194967196

Offset

0,1

Links

Robert Israel, Table of n, a(n) for n = 0..3318

Formula

a(n) = A035043(A000079(n)). - Robert Israel, Feb 12 2019

Maple

f:= proc(n) local L, i;
  L:= subs([2=1, 1=2], convert(2^n, base, 10));
  add(L[i]*10^(i-1), i=1..nops(L))
end proc:
map(f, [$0..50]); # Robert Israel, Feb 12 2019

Prog

(Python)
def A306392(n):
    return int(''.join('1' if d == '2' else ('2' if d == '1' else d) for d in str(2**n))) # Chai Wah Wu, Feb 12 2019

Crossrefs

Cf. A000079, A035043, A323948 (sorted version).

Sequence in context: A303632 A133267 A145864 * A182739 A359132 A076014

Adjacent sequences: A306389 A306390 A306391 * A306393 A306394 A306395

Keyword

nonn,base

Author

Paul Curtz and N. J. A. Sloane, Feb 12 2019

Status

approved