centered triangular number造句

• 136 is a triangular number, a centered triangular number and a centered nonagonal number.
• Ten is also a triangular number, a centered triangular number, and a tetrahedral number.
• Each centered triangular number from 10 onwards is the sum of three consecutive regular triangular numbers.
• 19 is the lowest prime centered triangular number, a centered hexagonal number and a Heegner number.
• 31 is a centered triangular number, the lowest prime centered pentagonal number and a centered decagonal number.
• Also each centered triangular number has a remainder of 1 when divided by three and the quotient ( if positive ) is the previous regular triangular number.
• The following image shows the building of the centered triangular numbers using the associated figures : at each step the previous figure, shown in red, is surrounded by a triangle of new points, in blue.