The given sequence is 2, 5, 18, 49, 154, and we need to find the next number in the sequence.

Pattern:
To find the pattern in the given sequence, let's look at the differences between consecutive terms.

2, 5, 18, 49, 154

The differences between consecutive terms are:

3, 13, 31, 105

Pattern in the Differences:
Upon analyzing the differences, we can observe that they are increasing with each term.

3, 13, 31, 105

To find the pattern in the differences, let's look at the differences between consecutive differences.

The differences between consecutive differences are:

10, 18, 74

Pattern in the Second Differences:
Upon analyzing the second differences, we can observe that they are also increasing with each term.

10, 18, 74

General Pattern:
From the above analysis, we can conclude that the given sequence follows a quadratic pattern.

The general pattern can be represented by the formula:

nth term = an^2 + bn + c

Using the Quadratic Formula:
To find the values of a, b, and c, we can substitute the first three terms of the sequence into the formula and solve the resulting system of equations.

Using the values 2, 5, and 18, we can set up the following equations:

a(1^2) + b(1) + c = 2
a(2^2) + b(2) + c = 5
a(3^2) + b(3) + c = 18

Simplifying the equations, we get:

a + b + c = 2
4a + 2b + c = 5
9a + 3b + c = 18

Solving this system of equations, we find:

a = 1
b = -1
c = 2

Calculating the Next Term:
Now that we have the values of a, b, and c, we can determine the next term in the sequence.

Using the formula:

nth term = an^2 + bn + c

we can substitute n = 6 (since we are finding the sixth term) and the values of a, b, and c:

6(1^2) + (-1)(6) + 2 = 6 - 6 + 2 = 2

Therefore, the next term in the sequence is 2.

Conclusion:
The next term in the sequence is 2. Among the given options, option 'D' (453) is the closest to the calculated value.