1, 11, 21, 1211, ?...What are the next numbers in the sequence?

Question

Add explanations to your answer. Please.

Answer 1

111221, 312211, 13112221, 1113213211, ...
OR
1231, 131221, 132231, 232221, 134211, ...
OR
3112, 211213, 312213, 212223, 114213, ...

Each is based on the digit makeup of the previous term, but I need one more term in the sequence to be sure of the rule.

Answer 2

1211=3 1's, 1 2=3112

A very fescinating sequence.

Answer 3

Not that old chestnut again!

Two meanings of a digit are being deliberately confused and concatenated, here,

(a) odd-numbered digits mean "how many of the thing being counted there are in the previous term" (number as an adjective)

(b) even-numbered digits mean "the thing that is to be counted in the previous term" (number as a noun)

1211 would be clear if it was written as

"one '2', one '1'"

with the word one being the adjective and the number 1 being the noun and the commas acting as separators and as punctuation to make the meaning clear.

But it is expressed deliberately unclearly, so as to confuse. I feel I am being manipulated and cheated when this happens. I am led to believe it is one thing, and it proves to be another. I fail to see the satisfaction in that.

This is not the genuine mathematical sequence it pretends to be. It belongs in puzzles not in maths.

Answer 4

111211
Explanation: Read the fifth number out loud:
one one, one two, one one.
Now try to compare this with the fourth number: 1211. We have one 1, one 2, and 1, 1 left behind. Do you understand the pattern?

Answer 5

AHHAHAHA this is so humorous my instructor purely gave us this riddle... no person figured it out, yet then he advised us. ok nicely the subsequent set is 13112221 because of the fact... it starts of with a million so then there is one one hense the 11 the subsequent it 21 because of the fact there are 2 ones interior the previous set, the subsequent is 111231 cuz there is one one, one 2 and 3 ones, next there are 3 ones, 2 twos, and one one, so the subsequent is one 3, one one, 2 twos and 2 ones. i understand that become prob. confussing yet all this is is the style of the style of numbers interior the previous set. i actual wish that helped. IAN

Answer 6

Another oft repeated question. Each number describes the previous
Read it like this:
1
One 1
Two 1's
One 2, One 1
Next
One 1, one 2, two 1s = 111221

Answer 7

1231

Answer 8

1, 11, 21, 1211, 111221
1 -- one 1, so 11
11 --- two 1s, so 21
21 --- one 2 and one 1
111221 --- one 1, one 2 and two 1s

Answer 9

111221

one 1
one 2
two 1

Answer 10

rt11guru was the first to get it right
next numbers are
111221, 312211, 13112221, 1113213211 etc. etc.