__,__,__,48,100,180,
294,448,648,__,__,__,.......Find the three numbers before and after given numbers in the series.
Building a differences table produces:
48 52 28 6
100 80 34 6
180 114 34 6
294 154 40 6
448 200 46 6
648 252 52 6
The
fixed third column (6) suggests the values come from a third
degree polynomial. Extending the differences table in both directions
gives
0,
4 and
18 as the initial values, and
900,
1210 and
1584 as the last.
Solution by differences
