Squares of numbers containing 1s form an amazing sequence:
| 11 | * | 11 | = | 121 |
| 111 | * | 111 | = | 12321 |
| 1111 | * | 1111 | = | 1234321 |
| 11111 | * | 11111 | = | 123454321 |
| 111111 | * | 111111 | = | 12345654321 |
| 1111111 | * | 1111111 | = | 1234567654321 |
| 11111111 | * | 11111111 | = | 123456787654321 |
| 111111111 | * | 111111111 | = | 12345678987654321 |
Do note, the total number of digits in the number appears as the central/middle digit within the product. For example, the number of digits in 11111 is 5; the product 123454321 shows 5 as the central digit.
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