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
Legendre symbol Legendre symbol In number theory, the Legendre symbol is a multiplicative function with values 1, −1, 0 that is a quadratic character modulo an odd prime number "p": its value on a (nonzero) quadratic residue mod "p" is 1 and on a non-quadratic residue ("non-residue") is −1. Its value on zero is 0. The Legendre symbol was introduced by Adrien-Marie Legendre in 1798 in the course of his attempts at proving the law of quadratic reciprocity. Generalizations of the symbol include the Jacobi symbol and Dirichlet characters of higher order. The notational convenience of the Legendre symbol inspired introduction of