What is the next number in the sequence? 4,5,7,11,19,...

The sequence appears to be increasing by a pattern where each number is the sum of the two preceding numbers.

Here's how you can work it out:

• Start with the first two numbers: 4 and 5.
• Add them together to get the third number: 4 + 5 = 9, but the third number is 7, not 9.
• Let's try a different approach. Subtract the first number from the second: 5 - 4 = 1. Add this result to the second number: 5 + 1 = 6. This is not the third number either.
• Another approach is to add the first number to the second number and then add 1: 4 + 5 + 1 = 10. This is closer to the third number, but it's still not 7.
• The correct approach is to add the first number to the second number and then subtract 2: 4 + 5 - 2 = 7. This gives us the third number.
• Apply the same approach to find the fourth number: 5 + 7 - 2 = 10, but the fourth number is 11, not 10.
• So, the pattern changes here. From the third number onwards, you add the two preceding numbers without subtracting 2: 5 + 7 = 12, but the fourth number is 11, not 12.
• Subtract 1 from the result: 12 - 1 = 11. This gives us the fourth number.
• Apply the same approach to find the fifth number: 7 + 11 - 1 = 17, but the fifth number is 19, not 17.
• So, the pattern changes again. From the fourth number onwards, you add the two preceding numbers and then add 1: 7 + 11 + 1 = 19. This gives us the fifth number.

Following this pattern, the next number in the sequence would be:

• 11 + 19 + 1 = 31.