export declare const CHARS = "BCDGHJKLNPQRSTWZbcdghjklnpqrstwz";
export declare const REGEX: RegExp;
/**
 * Encodes a non-negative bigint into a Basepura string.
 *
 * @param n - A non-negative bigint to encode
 * @returns A Basepura string representation of the input number
 * @throws {RangeError} If the input is negative
 */
export declare function encode(n: bigint): string;
/**
 * Decodes a Basepura string into a bigint.
 *
 * @param s - A Basepura string to decode
 * @returns The decoded bigint value
 * @throws {RangeError} If the input is empty or contains invalid characters
 */
export declare function decode(s: string): bigint;
/**
 * Checks if a string is a valid Basepura string.
 *
 * @param s - A string to validate
 * @returns True if the string contains only valid Basepura characters, false otherwise
 */
export declare function isBasepura(s: string): boolean;