Find the missing number in the given number series. 5, 6, 16, ?, 244, 1245

This series combines two operations: first, add the square of consecutive integers (1²=1, 2²=4, 3²=9), then subtract consecutive squares starting from 3². 5+1=6, 6+4=10 (not 16), so the pattern is: add 1² (1), add 4 (actually 2²+9=16), then add decreasing squares. The correct continuation is 16+41=57, 57+187=244. The pattern involves squares with position-based modifications.