MathDB

3

Part of 1991 Federal Competition For Advanced Students

Problems(1)

find the number of squares

Source: Austria 1991

7/10/2009
Find the number of squares in the sequence given by a_0\equal{}91 and a_{n\plus{}1}\equal{}10a_n\plus{}(\minus{}1)^n for n≥0. n \ge 0.
inductionmodular arithmeticquadraticsnumber theory unsolvednumber theory