A085741 a(n) = T(n)^n, where T() are the triangular numbers (A000217).

1, 1, 9, 216, 10000, 759375, 85766121, 13492928512, 2821109907456, 756680642578125, 253295162119140625, 103510234140112521216, 50714860157241037295616, 29345269354638035222576971

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Formula

a(n) = ((n*(n+1))/2)^n. - Vincenzo Librandi, Sep 14 2011

Example

a(3) = T(3)^3 = 6^3 = 216.

Maple

a:=n->mul(sum(j, j=1..n), k=1..n): seq(a(n), n=0..13); # Zerinvary Lajos, Jun 02 2007

Mathematica

With[{rnn=Range[20]}, Join[{1}, First[#]^Last[#]&/@Thread[ {Accumulate[ rnn],  rnn}]]] (* Harvey P. Dale, Dec 08 2013 *)

Prog

(PARI) a(n) = (n*(n+1)/2)^n; \\ Michel Marcus, Feb 19 2019
(Magma) [((n*(n+1))/2)^n: n in [0..20]]; // Vincenzo Librandi, Sep 14 2011

Crossrefs

Cf. A000217.

Essentially the same as A061718.

Cf. A000312, A062206, A212333.

Sequence in context: A064633 A084942 A061718 * A211044 A152288 A179153

Adjacent sequences: A085738 A085739 A085740 * A085742 A085743 A085744

Keyword

nonn,easy

Author

Jon Perry, Jul 21 2003

Extensions

More terms from Ray Chandler, Nov 09 2003

Status

approved