Smallest pandigital number perfect square

1.1k Views Asked by At

What is the smallest $9$-digit number that has all the digits from $1$ to $9$ exactly once and is also a perfect square?

Please give me a method that doesn't involve programming.

1

There are 1 best solutions below

0
On

Just look up A036744, the penholodigital squares.

The possible solutions are
139854276, 152843769, 157326849, 215384976, 245893761, 254817369,
326597184, 361874529, 375468129, 382945761, 385297641, 412739856,
523814769, 529874361, 537219684, 549386721, 587432169, 589324176,
597362481, 615387249, 627953481, 653927184, 672935481, 697435281,
714653289, 735982641, 743816529, 842973156, 847159236, 923187456

With square roots
11826, 12363, 12543, 14676, 15681, 15963,
18072, 19023, 19377, 19569, 19629, 20316,
22887, 23019, 23178, 23439, 24237, 24276,
24441, 24807, 25059, 25572, 25941, 26409,
26733, 27129, 27273, 29034, 29106, 30384