There is a series of numbers 1, 4, 91, 625, 36... They are arranged in a certain order, then the number 1998 is different from the number 1999

There is a series of numbers 1, 4, 91, 625, 36... They are arranged in a certain order, then the number 1998 is different from the number 1999

1=1²
4=2²
9=3²
……
The number of 1998 is 178;
The number of 1999 is 1999-178;
So 1998 & # 178; - 1999 & # 178; = (1998-1999) × (1998 + 1999) = - 3997

The number of an array arranged according to a certain rule: 1, 2, 3, 2, 4, 6, 3, 6, 9, etc?
urgent need

1(1,2,3,)
2(1,2,3,)
3(1,2,3,)
……
33(1,2,3,)
The 99th number is 33 × 3 = 99
The sum of the first 20 is 1 (1 + 2 + 3) + 2 (1 + 2 + 3) + 3 (1 + 2 + 3) + +6(1+2+3)+7(1+2)
＝6(1+2+3+4+5+6)+21
＝6×21+21＝147

Fill in the numbers according to the rules: 1,4,9,16, {}, 36, {}

1,4,9,16,{25 },36,{ 49}
Each is the square of one
The square of 2
The square of 3
.

A multi bit number is & nbsp; 14916236496481 , the 100th number from left to right is______ ．

The square of 1, 2, 3 is one digit, the square of 4-9 is two digit, the square of 10-31 is three digit, 1 × 3 + 2 × 6 + 3 × 22 = 81 (bit); the square of two digits from 32 is four digit, 4 × 4 = 16100-81-16 = 3 (bit); then the 100th digit is the third digit of 36's Square, 362 = 1296, so the 100th digit is 9