Infinity on High with a 54% decline during a post-Grammy week. The album rose to number three in its third week with 79,000 units sold. In its fourth week, the disc slipped to number four and sold 67,000 copies. "Infinity on High"s sales again fell in its fifth week, moving 58,000 copies and descending to number eight on the chart. In its sixth and last week in the top ten it fell to number nine and sold 43,000 copies. In April 2007, the album was certified Platinum by the Recording Industry Association of America (RIAA), denoting the shipment of one million copies. It
Jacobi symbol Jacobi symbol The Jacobi symbol is a generalization of the Legendre symbol. Introduced by Jacobi in 1837, it is of theoretical interest in modular arithmetic and other branches of number theory, but its main use is in computational number theory, especially primality testing and integer factorization; these in turn are important in cryptography. For any integer "a" and any positive odd integer "n", the Jacobi symbol is defined as the product of the Legendre symbols corresponding to the prime factors of "n": where is the prime factorization of "n". The Legendre symbol is defined for all integers "a" and all