👉 Octingentenary is a concept in mathematics that refers to the number of digits required for representation or description of an octagonal number. An octagonal number, also known as an octonacci number, is an integer that can be represented as the sum of the first n terms of an arithmetic sequence where each term is the next Fibonacci number plus 1. The term "octingentenary" comes from this concept because it represents the total number of digits required to represent a given octagonal
