No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
r | 15 | 30 | 45 | 60 | 75 | 90 | 105 | 120 | 135 | 150 | 165 | 180 | 195 | 210 | 225 | 240 | 255 | 270 | 285 | 300 |
N (r) | 47 | 93 | 191 | 297 | 423 | 593 | 725 | 879 | 1011 | 1113 | 1239 | 1317 | 1405 | 1439 | 1473 | 1493 | 1511 | 1517 | 1519 | 1521 |