A061658 Numbers k > 1 such that, in base 4, k and k^2 contain the same digits in the same proportion.

45, 165, 180, 657, 660, 720, 882, 2165, 2193, 2331, 2625, 2628, 2640, 2880, 3362, 3470, 3528, 3606, 3683, 3825, 8285, 8294, 8337, 8381, 8477, 8493, 8519, 8525, 8660, 8721, 8772, 8817, 9069, 9282, 9324, 9479, 9507, 9869, 9969, 10185, 10349, 10353, 10500, 10512

Offset

1,1

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Example

45 = 231_4 and 45^2 = 133221_4.

Maple

p:= n-> add(x^i, i=convert(n, base, 4)):
a:= proc(n) option remember; local k;
      for k from 1+`if`(n=1, 0, a(n-1))
      while p(k)*2<>p(k^2) do od; k
    end:
seq(a(n), n=1..50);  # Alois P. Heinz, May 10 2015

Crossrefs

Cf. A061656, A061657, A061659, A061660, A061661, A061662, A061663, A114258, A061664.

Sequence in context: A173371 A288669 A305069 * A254147 A271737 A280887

Adjacent sequences: A061655 A061656 A061657 * A061659 A061660 A061661

Keyword

base,easy,nonn

Author

Erich Friedman, Jun 16 2001

Extensions

Offset changed to 1 by Alois P. Heinz, May 10 2015

Status

approved