|
| |
|
|
A070073
|
|
Number of distinct cuboids with integer sides <=n and cube-free volume.
|
|
1
| |
|
|
1, 3, 8, 11, 23, 33, 57, 57, 70, 95, 142, 156, 220, 271, 338, 338, 441, 480, 609, 658, 775, 896, 1090, 1090, 1220, 1387, 1387, 1468, 1737, 1882, 2197, 2197, 2474, 2735, 3078, 3153, 3592, 3923, 4328, 4328, 4861, 5195, 5794
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
LINKS
| Eric Weisstein's World of Mathematics, cube-free numbers.
|
|
|
EXAMPLE
| There are eleven cuboids with sides <=4 having a cube-free volume: 1 X 1 X 1, 1 X 1 X 2, 1 X 1 X 3, 1 X 1 X 4, 1 X 2 X 2, 1 X 2 X 3, 1 X 3 X 3, 1 X 3 X 4, 2 X 2 X 3, 2 X 3 X 3 and 3 X 3 X 4 whereas 1 X 2 X 4, 1 X 4 X 4, 2 X 2 X 2, 2 X 2 X 4, 2 X 3 X 4, 2 X 4 X 4, 3 X 3 X 3 and 4 X 4 X 4 are not cube-free; therefore a(4)=11.
|
|
|
CROSSREFS
| Cf. A004709, A070072.
Sequence in context: A182759 A022121 A171672 * A058565 A170901 A201882
Adjacent sequences: A070070 A070071 A070072 * A070074 A070075 A070076
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 21 2002
|
| |
|
|
