# Next number in a sequence

• cjbreen
In summary, the next number in the sequence is 63, and the pattern can be represented by the formula T(n) = (n2) - (-1)n. This was found by calculating the differences between the numbers in the sequence and taking the sum of the last two digits in the first set and subtracting the first digit, then repeating the process with the second set. Another method used was adding or subtracting values from each number in the sequence to get the next number.

#### cjbreen

What is the next number in the sequence? 2, 3, 10, 15, 26, 35, 50, ?

Is this some sort of homework question?

63
1st..(1*1)+1 odd
2nd (2*2)-1 even
3rd (3*3)+1 odd
...
8th (8*8)-1 even

yeah i got 63 too, but in a different way i think.
basically, the differences between them respectively, are 1, 7, 5, 11, 9, and 15.
divide it like this: 1, 7, 5, and 11, 9, 15
then take the sum of the last two digits in the first set, and subtract the first. so in this case, 7 + 5 -1.
you get 11, which is the next difference.
do this with the second set of 11, 9, and 15 and you'll get 13 as the next difference, meaning that 50 + 13 should be the next number.
that's how i got 63.
let me know what you guys think.

nabeelr said:
yeah i got 63 too, but in a different way i think.
basically, the differences between them respectively, are 1, 7, 5, 11, 9, and 15.
divide it like this: 1, 7, 5, and 11, 9, 15
then take the sum of the last two digits in the first set, and subtract the first. so in this case, 7 + 5 -1.
you get 11, which is the next difference.
do this with the second set of 11, 9, and 15 and you'll get 13 as the next difference, meaning that 50 + 13 should be the next number.
that's how i got 63.
let me know what you guys think.

This is what I was thinking as well. I suspect it.anoopk's solution was probably the original intention. Seems a bit less random.

Last edited:
i got 63, too, but a different way, i got it by 2+1=3, add 6 to the one, 3:7=10, subtract 2 from the 7, add the number you grt<5> 15, add the 6 to 5 get 11 add 11 get 26 subtract 2 get 9 add 9 get 35 add 6 get 15 add 15 to 35 get 50 subtract 2 get 13 add 13 to 50 get 63 yay i win

i got it a different way: =2+1=3 add 6 to 1 get 7 add 7 get 10 subtract 2 get 5 add 5 get 15 add 6 get 11 add 11 get 26 subtract 2 get 9 add 9 get 35 add 6 get 15 add 15 get 50 subtract to add 13 get 63 =[] this is the immature way to do it but i got it done in 3 minutes and I am only 12...

alexk174 said:
i got it a different way: =2+1=3 add 6 to 1 get 7 add 7 get 10 subtract 2 get 5 add 5 get 15 add 6 get 11 add 11 get 26 subtract 2 get 9 add 9 get 35 add 6 get 15 add 15 get 50 subtract to add 13 get 63 =[] this is the immature way to do it but i got it done in 3 minutes and I am only 12...
that was too easy

10 10 11 12 15 16 21

S(n) = 2, 3, 10, 15, 26, 35, 50, 63, ... , (n2) - (-1)n

T(n) = (n2) - (-1)n