Centered octagonal number
= Centered octagonal number
{wiki=Centered_octagonal_number}
A centered octagonal number is a type of figurate number that represents a pattern of dots arranged in an octagonal shape. The formula to find the nth centered octagonal number is given by: \\\[ C_n = 3n^2 - 3n + 1 \\\] where \\(C_n\\) is the nth centered octagonal number and \\(n\\) is a positive integer (1, 2, 3, ...).