111, A Harshad number: 111/(1+1+1) = 3x37
111 = 12 × 3 + 45 + 6 + 7 + 8 + 9
111 = 9 × 8 + 7 + 6 + 5 × 4 + 3 + 2 + 1
111 = 0^5 + 1^8 − 2^9 + 3^3 − 4^7 + 5^6 + 6^4 + 7^2 + 8^1 + 9^0
111 divides 38^2 - 1.
111 = 222/2
111 = 333/3
...
111 = 999/9
Strobogrammatic number: the same upside down.
Number k such that k^2 + 2 is prime
Magic Square Numbers 1 to 36 and Sum 111
| 1 | 35 | 4 | 33 | 32 | 6 |
| 25 | 11 | 9 | 28 | 8 | 30 |
| 24 | 14 | 18 | 16 | 17 | 22 |
| 13 | 23 | 19 | 21 | 20 | 15 |
| 12 | 26 | 27 | 10 | 29 | 7 |
| 36 | 2 | 34 | 3 | 5 | 31 |
Björner-Welker sequence: 2^n*(n^2 + n + 2) - 1. n = 3
The ring of integers of the field Q(sqrt(-111)) has class number 8.
111 cannot be written as a sum of 3 squares. (Integers that are not a sum of three squares)
Semiprime (Product of 2 Primes)
Semiprime s such that s-/+2 are primes.
Factors: 1, 3, 37, 111
Representations, Binary to Hexadecimal:
1101111_2
11010_3
1233_4
421_5
303_6
216_7
157_8
133_9
a1_11
93_12
87_13
7d_14
76_15
6f_16
Undergraduate Texts in Mathematics
Graduate Studies in Mathematics
