Science Fair Project Encyclopedia
Heptagonal number
A heptagonal number is a figurate number that represents a heptagon. The heptagonal number for n is given by the formula n(5n - 3)/2, with n > 0. The first few heptagonal numbers are
1, 7, 18, 34, 55, 81, 112, 148, 189, 235, 286, 342, 403, 469, 540, 616, 697, 783, 874, 970
The parity of heptagonal numbers follows the pattern odd-odd-even-even. Like square numbers, the digital root in base 10 of a heptagonal number can only be 1, 4, 7 or 9.
Five times a heptagonal number, plus 1 equals a triangular number.
10-26-2009 08:16:03
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details