/**
 * Creates a band matrix with specified lower and upper bandwidths
 *
 * @param n Size of the square matrix
 * @param lband Lower bandwidth (number of non-zero diagonals below main diagonal)
 * @param uband Upper bandwidth (number of non-zero diagonals above main diagonal)
 * @returns A 2D array representing the band matrix with 1s in the band and 0s elsewhere
 */
export declare function band(n: number, lband: number, uband: number): number[][];