The MathResource
recursion formula,
recursion clause, or inductive step, n. the part of a recursive definition (or algorithm) that specifies the step by which each element of the sequence is generated from the preceding; for example, given the base clause f(0) = 5, the schema
f(n + 1) = f(n) + 3
specifies the successive terms of the arithmetic progression 5, 8, 11, 14,....