Talk:Hexagonal number

needs illustrations

This article needs illustrations, like the Triangular number article.--69.87.194.231 23:24, 11 February 2007 (UTC)[reply]

Gaps

Looks like a few more dots could fit in... 128.146.46.2 (talk) 15:59, 13 March 2009 (UTC)[reply]

Indeed, what does this picture mean? The second number should be 7 (one dot in the center, six around). The third should be 19, etc. — Monedula (talk) 17:22, 25 November 2013 (UTC)[reply]

The numbers defined using hexagons with a dot at the center are the centered hexagonal numbers, which are distinct from the hexagonal numbers. As in the case of the pentagonal number, the n-th hexagonal number gives the number of distinct dots in a pattern of dots consisting of the outlines of regular hexagons which are overlaid so that they share a common vertex. -- Toshio Yamaguchi 20:46, 25 November 2013 (UTC)[reply]