问如何在R中完成Fibonacci序列的评估？

EN

   len <- 50
    fibvals <- numeric(len)
    fibvals[1] <- 1
    fibvals[2] <- 1
    for(i in 3:len) { fibvals[i] <- fibvals[i-1]+fibvals[i-2]}
    fibvals
     [1]           1           1           2           3           5
     [6]           8          13          21          34          55
    [11]          89         144         233         377         610
    [16]         987        1597        2584        4181        6765
    [21]       10946       17711       28657       46368       75025
    [26]      121393      196418      317811      514229      832040
    [31]     1346269     2178309     3524578     5702887     9227465
    [36]    14930352    24157817    39088169    63245986   102334155
    [41]   165580141   267914296   433494437   701408733  1134903170
    [46]  1836311903  2971215073  4807526976  7778742049 12586269025

    # Creates a variable called len in which the value 50 is stored
    # Creates a var called fibvals, which is a numeric datatype, which should have len (50) vals
    # Sets the value of the first entry in fibvals to 1
    # Sets the value of the second entry in fibvals to 1
    # Loop - "for (i in 3:len)" dictates that the loop should be executed between step 3 and step 50 (denoted by "len")
    # Loop - Defines a loop step "i" as being the result of the (current i - the before it) + (current i - i two before it)
    # Loop - Example 5 = (5-3) + (5-2) OR 2 + 3 = 5 | Example 21 = (21-13) + (21-8) OR  8 + 13 = 21 

    is.even <- function(x){ x %% 2 == 0 }

    # Creates a UDF to check if values are odd or even by using modulo. 
    If the remainder is 0 when any value is divided by 2, it is an even number 

is.even(fibvals)

 [1] FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE
[11] FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE
[21]  TRUE FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE  TRUE
[31] FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE
[41] FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE

# Evaluates all Fibonacci values on odd or even property