

A097571


Numbers n such that triangular number t(n) (see A000217) = n(n+1)/2 is a product of three consecutive integers.


4




OFFSET

1,2


COMMENTS

Replacing "three" by "two" we get A001652.
Replacing "three" by "N" we get: {15} for N = 4 and 5, {2079} for N = 6 and no solutions for N >= 7.  J. B. M. Melissen.
t(a(n)) equals x*(x+1)*(x+2) for x = [0, 1, 4, 5, 9, 56, 636]_n.  Zak Seidov, Jun 21 2013


LINKS

Table of n, a(n) for n=1..7.
S. P. Mohanty, Which triangular numbers are products of three consecutive integers?, Acta Mathematica Hungarica 1991, Volume 58, Issue 12, pp 3136.


CROSSREFS

Cf. A000217, A001219, A001652.
Sequence in context: A111517 A083545 A224872 * A048087 A316751 A001897
Adjacent sequences: A097568 A097569 A097570 * A097572 A097573 A097574


KEYWORD

nonn,fini,full


AUTHOR

N. J. A. Sloane, Aug 29 2004


STATUS

approved



