Author Topic: Find the rule of these numbers (Read 1148 times) Tweet Share

peterpan101 · « **on:** February 11, 2013, 07:58:38 pm »

this is not a further question
it was just an activity wanted to see if i could do and it but i cant

1 2 3 4 5 6
1 3 6 10 15 21

Smiley_ · « **Reply #1 on:** February 11, 2013, 08:34:21 pm »

you can put these types of questions in the mathematics section. but any way

it probably involves x^2, or 2x

edit: i was a bit off lol

BubbleWrapMan · « **Reply #2 on:** February 11, 2013, 09:29:09 pm »

I don't suppose the third number is supposed to be a 6?

If not I got nothing

peterpan101 · « **Reply #3 on:** February 11, 2013, 09:37:13 pm »

yes it is sorry

BubbleWrapMan · « **Reply #4 on:** February 11, 2013, 09:37:57 pm »

Then it's

1
1+2
1+2+3
1+2+3+4
1+2+3+4+5
1+2+3+4+5+6

Daenerys Targaryen · « **Reply #5 on:** February 11, 2013, 09:40:30 pm »

I had $\frac{x^2}{2}+\frac{x}{2}$

BubbleWrapMan · « **Reply #6 on:** February 11, 2013, 09:54:38 pm »

I had $\frac{x^2}{2}+\frac{x}{2}$

Yep, that's the formula for the sum of the first x natural numbers

Smiley_ · « **Reply #7 on:** February 12, 2013, 10:25:14 am »

how about a challenge guys what about

just
1 3 6 10 15 21?

plato · « **Reply #8 on:** February 12, 2013, 04:00:33 pm »

how about a challenge guys what about

just
1 3 6 10 15 21?

What about t(n+1) = n + t(n) and t(1) = 1

Markkiieee · « **Reply #9 on:** February 12, 2013, 08:55:56 pm »

I don't suppose the third number is supposed to be a 6?

If not I got nothing

You are INCORRECT

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