c# - "myList.Count" is less then the amount of elements inside the list -

i have task write program takes numbers , step input.
must make sequence of binary representation of numbers , destroy bits @ positions 1, 1*step, 2*step, 3*step...
here code:

using system; using system.collections.generic;  class bitkiller {     static void main()     {         int             amountnumbers = int.parse(console.readline()),             step = int.parse(console.readline()),             counter = 0,             number = 0         ;         int[]              numbin= new int[8],             numbers = new int[amountnumbers]         ;         var sequence = new list<int>();         for(int = 0; < amountnumbers; i++)         {             numbers[i] = int.parse(console.readline());             numbin = tobin(numbers[i]);             sequence.insertrange(counter * 8, numbin);             foreach(int b in sequence)             {                 console.write(b);             }             console.writeline("");             counter++;         }         if(step == 1)         {             console.writeline(0);             return;         }         for(int = sequence.count; >= 0; i--)         {                if(i % step == 1)             {                 sequence.removeat(i);             }         }         console.writeline("list count = {0}", sequence.count);         if(sequence.count % 8 != 0)         {             int padding = 8 - (sequence.count % 8);             for(int = 0; < padding; i++)             {                 sequence.add(0);             }         }         foreach(int b in sequence)         {             console.write(b);         }         console.writeline("");         for(int = 7, power = 0, y = 0; y < sequence.count; i--, y++, power++)         {             number = number + (sequence[i]) * topower(2, power);              if(i == 0)             {                 console.writeline("result = {0}", number);                 sequence.removerange(0, 8);                 foreach(int b in sequence)                 {                     console.write(b);                 }                 console.writeline("");                 number = 0;                 = 7;                 y = 0;                 power = 0;             }         }     }      static int[] tobin(int number)     {         var binsequence = new int[8];         for(int = 7; >= 0; number /= 2, i--)         {             if(number % 2 == 0 || (number == 0 && >= 0))             {                 binsequence[i] = 0;             }             else             {                 binsequence[i] = 1;             }         }         return binsequence;     }      static int topower(int number, int power)     {         int numberreturn = number;         if(power == 0)         {             return 1;         }         if(number == 1)         {             return number;         }         for(int = 0; < power - 1; i++)         {             numberreturn = numberreturn * number;         }         return numberreturn;     } } 

now, there couple of print lines can see binary numbers coming input numbers.
in short program converts numbers lists containing '1' , '0' , removes values list according formula.
main question why is:

sequence.count 

returning 22, when there 24 '1's inside list.
test following input: 3,19,255,255,255.
result be: 255, 254, 252, while correct output 255, 255, 252.

it happening, because of code:

if(sequence.count % 8 != 0) {     int padding = 8 - (sequence.count % 8);     for(int = 0; < padding; i++)     {         sequence.add(0);     } } 

because sequence.count 22 ( why? ) condition true , following loop replacing last 2 '1's 2 zeros.
causing wrong output.
point.
why sequence.count equal 22, when there 24 '1's in list.

sorry, if bit long , confusing, posted whole code, because have no idea , how interfering cause issue.

you removing 2 items list in code:

for(int = sequence.count; >= 0; i--) {        if(i % step == 1)     {         sequence.removeat(i);     } } 

with example input gave, sequence.removeat being called when == 20 , when == 1. there 24 items, removed 2 of them.