User blog:Qq1010903229/My C Function

=Definition = C(n) is the maximum return value of possible C programs with at most n characters (ignoring whitespace). If no program with at most n characters exists, C(n)=-1.

=Calculation = C(1)=C(2)=C(3)=C(4)=C(5)=C(6)=C(7)=-1 because no program with length 1-7 exists.

C(8)=0 because this program returns 0: main{} C(9)=C(10)=C(11)=C(12)=C(13)=C(14)=C(15)=0.

C(16)=9 because this program returns 9: main{return 9;} C(17)=99 because this program returns 99: main{return 99;} C(18)=999  because this program returns 999: main{return 999;} C(19)=9999  because this program returns 9999: main{return 9999;} C(20)=\(9\times 2^99\) because this program returns \(9\times 2^99\): main{return 9<<99;}