fibonacci w/ array tracking

#import <Foundation/Foundation.h>

@interface Fibonacci: NSObject {
        NSMutableArray *calculated;
    }
    - (int) getNumber: (int) n;
@end

@implementation Fibonacci
    - (id) init {
        self = [super init];
        calculated = [NSMutableArray array];
        for (int i = 0; i < 2; i++) {
            [calculated addObject: [NSNumber numberWithInt: 1]];
        }
        return self;
    }
    - (int) getNumber: (int) n {
        if (n > calculated.count - 1) {
            [calculated addObject: [NSNumber numberWithLong: [self getNumber: n - 1] + [self getNumber: n - 2]]];
        }
        return [[calculated objectAtIndex: n] intValue];
    }
@end

int main() {
    Fibonacci *fib = [[Fibonacci alloc] init];
    for (int i = 0; i < 25; i++) {
        NSLog(@"\nThe %dth number in the Fibonacci Sequence is %d", i, [fib getNumber: i]);
    }
}