cp's OEIS Frontend

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.

A386756 a(n) is the number of sets of distinct four-cuboid combinations that fill an n X n X n cube excluding combinations that contain cube-shaped cuboids.

Original entry on oeis.org

0, 0, 2, 10, 43, 81, 177, 260, 458, 605, 931, 1169, 1656, 1995, 2687, 3145, 4063, 4674, 5850, 6617, 8102, 9044, 10852, 12008, 14172, 15540, 18116, 19714, 22711, 24585, 28035, 30176, 34142, 36569, 41053, 43817, 48852, 51939, 57593, 61021, 67291, 71118, 78036, 82241, 89882
Offset: 1

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Author

Janaka Rodrigo, Aug 01 2025

Keywords

Comments

Alternatively, a(n) is the number of ways to decompose a (n,n,n) triplet into sets of four unordered triplets of the form (x,y,z) without having x=y=z in any of the triplets.

Examples

			There are 12 sets of distinct four-cuboid combinations filling 4 X 4 X 4 cube according to A384311(4), only two combinations containing cubes listed below,
   {(1,1,1), (1,1,3), (1,3,4), (3,4,4)},
   {(1,3,3), (3,3,3), (1,3,4), (1,4,4)}.
Therefore, a(4) = 12-2 = 10.
		

Crossrefs

Cf. A384311.