is_kaprekar <- function(n) {
 
  nch <- unlist(strsplit(format(n^2, scientific = FALSE), ""))
  len <- length(nch)
 
  if(len < 2) {
    return(FALSE)
  }
 
  for(i in 1:(len - 1)) {
    first <- as.integer(paste0(nch[1:i], collapse = ""))
    second <- as.integer(paste0(nch[(i+1):length(nch)], collapse = ""))
    if(first + second == n && (second > 0)) {
      cat(first, "+", second, "=", n,"\n")
      return(TRUE)
    }
  }
 
  return(FALSE)
}
 
for(i in 1:9000) {
  is_kaprekar(i)
}

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