A027484 a(n) = n*(n^4-1)/2.

15, 120, 510, 1560, 3885, 8400, 16380, 29520, 49995, 80520, 124410, 185640, 268905, 379680, 524280, 709920, 944775, 1238040, 1599990, 2042040, 2576805, 3218160, 3981300, 4882800, 5940675, 7174440, 8605170, 10255560, 12149985

Offset

2,1

Comments

Row sums in a pandiagonal magic 4D-cube with entries (0..n^4-1).

Can be computed from the fourth power of a matrix constructed with the Stirling numbers of the first kind (see A027479).

Links

Vincenzo Librandi, Table of n, a(n) for n = 2..1000

S. Gartenhaus, Odd Order Pandiagonal Latin and Magic Cubes in Three and Four Dimensions, arXiv:math/0210275 [math.CO], 2002.

Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).

Formula

From Chai Wah Wu, Apr 08 2021: (Start)

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n > 7.

G.f.: 15*x^2*(x + 1)^2/(x - 1)^6. (End)

Mathematica

Table[(m^5 - m)/2, {m, 34}] (* Zerinvary Lajos, Mar 21 2007 *)

Prog

(Magma) [n*(n^4 - 1)/2: n in [2..50]]; // Vincenzo Librandi, Dec 29 2012
(PARI) a(n)=n*(n^4-1)/2 \\ Charles R Greathouse IV, Oct 21 2022

Crossrefs

First subdiagonal of A027479.

Sequence in context: A259746 A139615 A196506 * A185542 A226989 A126898

Adjacent sequences: A027481 A027482 A027483 * A027485 A027486 A027487

Keyword

nonn,easy

Author

Olivier Gérard

Status

approved