從1到200這些正整數中,可表示成二個不同的非負整數(即包含0)之平方和的數共有
個。
(2008青少年數學國際城市邀請賽初賽)
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
0 | 1 | 4 | 9 | 16 | 25 | 36 | 49 | 64 | 81 | 100 | 121 | 144 | 169 | 196 |
1 | | 5 | 10 | 17 | 26 | 37 | 50 | 65 | 82 | 101 | 122 | 145 | 170 | 197 |
2 | | | 13 | 20 | 29 | 40 | 53 | 68 | 85 | 104 | 125 | 148 | 173 | 200 |
3 | | | | 25 | 34 | 45 | 58 | 73 | 90 | 109 | 130 | 153 | 178 | 205 |
4 | | | | | 41 | 52 | 65 | 80 | 97 | 116 | 137 | 160 | 185 | 212 |
5 | | | | | | 61 | 74 | 89 | 106 | 125 | 146 | 169 | 194 | 221 |
6 | | | | | | | 85 | 100 | 117 | 136 | 157 | 180 | 205 | 232 |
7 | | | | | | | | 113 | 130 | 149 | 170 | 193 | 218 | 245 |
8 | | | | | | | | | 145 | 164 | 185 | 208 | 233 | 260 |
9 | | | | | | | | | | 181 | 202 | 225 | 250 | 277 |
10 | | | | | | | | | | | 221 | 244 | 269 | 296 |
11 | | | | | | | | | | | | 265 | 290 | 317 |
12 | | | | | | | | | | | | | 313 | 340 |
13 | | | | | | | | | | | | | | 365 |
補充一題類似題
How many of the integers between 1 and 1000, inclusive, can be expressed as the difference of the squares of two nonnegative integers?
(1997AIME,
http://www.mathlinks.ro/viewtopic.php?p=393578)