Question

what is the next number in this sequence: 1 11 21 1211 111221 312211 13112221?

Answer 1

1113213211 is next in sequence

Answer 2

Step-by-step explanation:

They’re “look-and-say” numbers. Each number in the sequence describes the digits of the previous number as you’d speak it:

1 (One)

11 (One one)

21 (Two ones)

1211 (One two, one one)

111221 (One one, one two, two ones)

312211 (Three ones, two twos, one one)

13112221 (One three, one one, two twos, two ones)

1113213211 (One one, one three, two ones, three twos, one one)

31131211131221 (Three ones, one three, one two, one one, one three, one two, two ones)