This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A070073 #21 Feb 16 2025 08:32:46 %S A070073 1,3,8,11,23,33,57,57,70,95,142,156,220,271,338,338,441,480,609,658, %T A070073 775,896,1090,1090,1220,1387,1387,1468,1737,1882,2197,2197,2474,2735, %U A070073 3078,3153,3592,3923,4328,4328,4861,5195,5794 %N A070073 Number of distinct cuboids with integer sides <= n and cubefree volume. %H A070073 Reinhard Zumkeller, <a href="/A070073/b070073.txt">Table of n, a(n) for n = 1..250</a> %H A070073 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Cubefree.html">Cubefree</a>. %e A070073 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. %o A070073 (Haskell) %o A070073 a070073 n = length [() | x <- [1..n], y <- [1..x], z <- [1..y], %o A070073 a212793 (x*y*z) == 1] %o A070073 -- _Reinhard Zumkeller_, May 27 2012 %Y A070073 Cf. A004709, A070072. %Y A070073 Cf. A212793. %K A070073 nonn %O A070073 1,2 %A A070073 _Reinhard Zumkeller_, Apr 21 2002