## October 12, 2009

### 15, 161, 1771, 19481, 214291,______?

Next number in the sequence
15, 161, 1771, 19481, 214291 is

Options:

1) 1942651
2) 135611101
3) 2424561
4) 1357101
5) 345372101
6) 1357201
7) 23651121
8) 1764924
9) 125461
10) 234255

Abhigya said...

2357121

Abhigya said...

2357121

Abhigya said...

Ignore my prev posts...
its (6) 1357201

beetrootchesself said...

I believe the answer is intended to be 2357201?

But it seems to me that the first term of the sequence does not fit and should perhaps be omitted?

Starting with 161 I agree, but starting with 15 I get:

15,165,1815,19965,219615,2415765

Or am I missing something very subtle?

Varun said...

its 1357201...

shashank said...

it should be

2357201

I agree with beetrootchesself that the first term just does not make sense.

Secret SquÃ¯rrel said...

It's 1357201 since there is no carry over.

Numbers are generated by adding together neighbouring digits of the preceding term and bracketting them between 1's. Start from the right and carry over tens to the next sum.

Carry overs from sum at right in bold.
15
161 : 1 (1+5) 1
1771 : 1 (1+6) (6+1) 1
19481 : 1 (1+7+1) (7+7) (7+1) 1
214291 : 1+1 (1+9+1) (9+4+1) (4+8) (8+1) 1
The first term is "2" because of the carry over from (1+9+1)
1357201 : 1 (2+1) (1+4) (4+2+1) (2+9+1) (9+1)1
The first term returns to "1" because there is no carry over from (2+1)

Anonymous said...

how the hell you all get 2357201?