All integers are either odd or even. If a number is a multiple of 2, it is even (even), which can be expressed as 2n; Otherwise, it is odd (singular), which can be expressed as 2n+ 1(n is an integer), that is, the remainder of odd (singular) divided by two is 1.
Odd number (English: odd number), also known as odd number, is even, and the odd number is 1, 3, 5, 7, 9. Even numbers can be represented by 2k, and odd numbers can be represented by 2k+ 1, where k is an integer.
The sequence: 1, 3, 5, 7, 9, ..., 2n- 1, ... is called an odd sequence, and the general term formula is
. It has a beautiful property: when n takes any positive integer, the sum of its first n terms is a complete square number, that is,
Odd columns can also be expressed from another angle: if
, when?
Any time.
, then the series.
It's an odd column.
Extended data
Regarding odd and even numbers, there are the following properties:
(1) Two consecutive integers must have an odd number and an even number;
(2) Odd number+odd number = even number; Even+odd = odd; Even number+even number+...+even number = even number;
(3) Odd-odd = even; Parity = odd number; Odd-even = odd;
(4) If A and B are integers, the parity of a+b and a-b is the same, that is, a+b and a-b are both odd or even;
(5) The product of n odd numbers is odd, and the product of n even numbers is even; If one of the formulas is even, the product is even;
(6) Odd numbers are 1, 3, 5, 7 and 9; Even numbers are 0, 2, 4, 6, 8;
(7) Divide the square of odd numbers by 2, 4 and 8, and the remainder is1;
(8) The square difference of any two odd numbers is a multiple of 2, 4 and 8.
(9) The odd number divided by 2 is 1.
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