Ѵ7 + Ѵ28 + Ѵ63 + ... +p =300Ѵ7

How many terms are in the sequence?

Ѵ7 + Ѵ28 + Ѵ63 + ... +p =300Ѵ7

√7 + 2√7 + 3√7 + .. + p = 300√7
1 + 2 + 3 + .. + p = 300

looks like an arithmetic series with
a = 1, d = 1, n = ? and Sn = 300
but Sn = (n/20[2a + (n-1)d]
(n/2)[2 + n-1] = 300
n(1+n) = 600
n^2 + n - 600 = 0
(n+25)(n-24) = 0
n = -25 or n = 24
but n stands for the number of terms, thus has to be positive
So you have 24 terms