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A070073 Number of distinct cuboids with integer sides <=n and cubefree volume. 2
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; text; internal format)
OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..250

Eric Weisstein's World of Mathematics, cubefree numbers.

EXAMPLE

There are eleven cuboids with sides <=4 having a cubefree 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 cubefree; therefore a(4)=11.

PROG

(Haskell)

a070073 n = length [() | x <- [1..n], y <- [1..x], z <- [1..y],

                         a212793 (x*y*z) == 1]

-- Reinhard Zumkeller, May 27 2012

CROSSREFS

Cf. A004709, A070072.

Cf. A212793.

Sequence in context: A022121 A171672 A341262 * A334539 A058565 A170901

Adjacent sequences:  A070070 A070071 A070072 * A070074 A070075 A070076

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Apr 21 2002

STATUS

approved

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Last modified May 7 16:00 EDT 2021. Contains 343652 sequences. (Running on oeis4.)