It's almost a cube

What is the next number in this sequence?

7, 10, 12, 19, 20, 30, _____

Note: I added another number as at first the pattern fit this too well.

Hint 1:

Try squaring the numbers

• oeis.org/A029904 did you try oeis? – Oray Oct 13 '18 at 16:36
• The only match in OEIS is A029904, but it begins with 0, 2, then 7, 10... – Hugh Oct 13 '18 at 17:35
• @Oray It's not oeis, its just a coincidence :P – PotatoLatte Oct 13 '18 at 18:06

I personally think (99.99%) this is very wrong but here goes,

(Q, W, E, R, T, and Y are all variables)

The pattern is just like the title said. The general idea is that Q x 1 + W x 2 + E x 3 + R x 4 + T x 5 + Y x 6 and so on is almost equal to a cube number

For 7

7 x 1 is very near to 8 = 2^3

For 7, 10

7 x 1 + 10 x 2 = 27 is equal to 27 = 3^3 (Don't know why. Must be a mistake?)

For 7, 10, 12

7 x 1 + 10 x 2 + 12 x 3 = 63 is almost equal to 64 = 4^3

For 7, 10, 12, 19

7 x 1 + 10 x 2 + 12 x 3 + 19 x 4 = 139 is quite near to 125 = 5^3 (A stretch, actually)

For 7, 10, 12, 19, 20

7 x 1 + 10 x 2 + 12 x 3 + 19 x 4 + 20 x 5 =239 is almost equal to 216 = 6^3 (Again, not sure about this)

However ,for 7, 10, 12, 19, 20, 30

7 x 1 + 10 x 2 + 12 x 3 + 19 x 4 + 20 x 5 + 30 x 6 = 419 while 7^3 = 343 (Quite far, actually)