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A381367
Number of possible configurations of an n dimensional Rubik's hypercube.
2
43252003274489856000, 1756772880709135843168526079081025059614484630149557651477156021733236798970168550600274887650082354207129600000000000000
OFFSET
3,1
COMMENTS
a(4) was calculated by Kamack and Keane (1982) and Velleman (1992). - Amiram Eldar, Mar 03 2025
LINKS
Harry J. Kamack and Tom R. Keane, The Rubik tesseract, unpublished manuscript, 1982; alternative link.
Giovanni Luca Marchetti, Rubik's Abstract Polytopes, arXiv:2502.13518 [math.CO], 2025.
Dan Velleman, Rubik's Tesseract, Mathematics Magazine, Vol. 65, No. 1 (1992), pp. 27-36.
FORMULA
See formula (26) on p. 16 of Marchetti.
MATHEMATICA
a[n_] := (1/(If[n >= 5, 1, 3]*2^(2^n + 2*(n-2)))) * Product[(n-i)!^(2^(n-i)*Binomial[n, i])*(2^(n-i) * Binomial[n, i])!, {i, 0, n-2}]; Array[a, 2, 3] (* Amiram Eldar, Feb 21 2025 *)
PROG
(PARI) a(n) = my(c=1); if (n<5, c=3); prod(i=0, n-2, ((n-i)!)^((2^(n-i)*binomial(n, i)))*((2^(n-i)*binomial(n, i))!))/(c*(2^(2^n+2*(n-2))));
CROSSREFS
Cf. A075152 (for a(3)), A381366.
Sequence in context: A219321 A020476 A231562 * A257370 A104283 A003852
KEYWORD
nonn
AUTHOR
Michel Marcus, Feb 21 2025
STATUS
approved