DefinitionAn integer is the sum of the elements of an integer. The calculation formula is Sn ≤ = 1 2 n (a1 ≤ + an ≤); where Sn ≤ is the number of the first n elements, a1 ≤ is the first element, and a is the nth element. Arithmetic systems play an important role in calculating numbers and analyzing associated data, especially in various financial fields, computer algorithms and discrete mathematical concepts. For example: the arithmetic sequence 3,7,11,15, ¡ The first n terms can be calculated using the formula Sn ≤ = 1 2 n (3 + (3 + (n − 1) 4)).