Square Root Day September 9, 1981 (9/9/81). Gordon remains the holiday's publicist, sending news releases to world media outlets. Gordon's daughter set up a Facebook group where people can share how they were celebrating the day. One suggested way of celebrating the holiday is by eating square radishes, or other root vegetables cut into shapes with square cross sections (thus creating a "square root"). Square Root Day occurs on the following dates each century: The number of years between consecutive Square Root Days in a century are consecutive odd numbers: 3, 5, 7, 9, 11, 13, 15, 17. This illustrates the fact that
Integer square root Integer square root In number theory, the integer square root (isqrt) of a positive integer "n" is the positive integer "m" which is the greatest integer less than or equal to the square root of "n", For example, formula_2 because formula_3 and formula_4. One way of calculating formula_5 and formula_6 is to use Newton's method to find a solution for the equation formula_7, giving the iterative formula The sequence formula_9 converges quadratically to formula_5 as formula_11. It can be proven that if formula_12 is chosen as the initial guess, one can stop as soon as to ensure that formula_14 For