A096662 Least nontrivial n-tuply triangular number.

3, 6, 21, 231, 26796, 359026206, 64449908476890321, 2076895351339769460477611370186681, 2156747150208372213435450937462082366919951682912789656986079991221

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Formula

a(n)=A007501(n). [From R. J. Mathar, Sep 04 2008]

Mathematica

f[n_] := n(n + 1)/2; Table[ Nest[f, 2, n], {n, 10}]

Crossrefs

Cf. A000217, A002817, A064322, A066370.

Sequence in context: A019053 A019054 A066986 * A236056 A347616 A280116

Adjacent sequences: A096659 A096660 A096661 * A096663 A096664 A096665

Keyword

nonn

Author

Robert G. Wilson v, Jul 02 2004

Status

approved