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A060080
Scaled sums of squares.
2
1, 5, 56, 1080, 31680, 1310400, 72576000, 5181926400, 463325184000, 50697529344000, 6663103856640000, 1035678099456000000, 187913434365296640000, 39357424864287129600000, 9424067526124476825600000, 2558178330075402338304000000, 781407199004850168791040000000
OFFSET
1,2
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..201 [offset shifted by Georg Fischer, May 11 2021]
FORMULA
a(n) = (Sum_{k=1..n} k^2)*((n-1)!)^2 = (n+1)!*(n-1)!*(2*n+1)/3!.
a(n) = A000330(n) * A001044(n-1).
MATHEMATICA
Table[(n + 1)! (n - 1)! (2 n + 1) / 3!, {n, 1, 30}] (* Vincenzo Librandi Jul 04 2018 *)
PROG
(PARI) a(n) = { (n + 1)!*(n - 1)!*(2*n + 1)/6 } \\ Harry J. Smith, Jul 01 2009
(Magma) [Factorial(n+1) * Factorial(n-1) * (2*n+1)/6: n in [1..20]]; // Vincenzo Librandi, Jul 05 2018
CROSSREFS
See Comments section at A060074.
Sequence in context: A132618 A371314 A192562 * A203522 A180874 A336243
KEYWORD
nonn
AUTHOR
Wolfdieter Lang, Mar 16 2001
EXTENSIONS
Offset changed from 0 to 1 by Georg Fischer, May 09 2021
STATUS
approved