The Odd Two's Let a, be the number of words (strings) of length n that can be made using the digits {0, 1, 2, 3 } with an odd number of twos. Find a recurrence relation for an and solve the recurrence. The first few values of an are calculated for you: a1 = 1 since all the one-letter words are: N a2 = 6 since all the two-letter words are: 20 21 23 02 12 32 a3 = 28 since all the three-letter words are: 020 021 023 002 012 032 120 121 123 102 112 132 320 321 323 302 312 332 200 201 203 210 211 213 230 231 233 222 The recurrence relation is: a1= an Use the * symbol for multiplication, and square brackets for subscripts. So to enter something like 3an-4 . 20-, type: 3*a[n-4]*2^ (3*n-5) The feedback must read "The variables found in your answer were: [a,-1, n]" otherwise your score will be 0 for this part. A solution to the recurrence relation is given by: an= The feedback must read "The variables found in your answer were: " otherwise your score will be 0 for this part