2 files changed, 55 insertions, 0 deletions
diff --git a/challenge-125/abigail/README.md b/challenge-125/abigail/README.md
index edbb6b6ea7..8fb1acbf4d 100644
--- a/challenge-125/abigail/README.md
+++ b/challenge-125/abigail/README.md
@@ -38,6 +38,7 @@ Output: -1
 * [Pascal](pascal/ch-1.p)
 * [Perl](perl/ch-1.pl)
 * [Python](python/ch-1.py)
+* [R](r/ch-1.r)
 * [Ruby](ruby/ch-1.rb)
 
 ### Blog
diff --git a/challenge-125/abigail/r/ch-1.r b/challenge-125/abigail/r/ch-1.r
new file mode 100644
index 0000000000..bd64758e3f
--- /dev/null
+++ b/challenge-125/abigail/r/ch-1.r
@@ -0,0 +1,54 @@
+#
+# See ../README.md
+#
+
+#
+# Run as: Rscript ch-1.r < input-file
+#
+
+introot <- function (square) {
+    return (floor (sqrt (square)))
+}
+
+stdin <- file ('stdin', 'r')
+repeat {
+    n <- readLines (stdin, n = 1)
+    if (length (n) == 0) {
+        break
+    }
+    n <- as.integer (n)
+    if (n <= 2) {
+        cat ("-1\n")
+        next
+    }
+
+    n_sq <- n * n
+    c    <- n + 1
+    c_sq <- n_sq + 2 * n + 1
+
+    while (2 * c - 1 <= n_sq) {
+        b_sq <- c_sq - n_sq
+        b    <- introot (b_sq)
+
+        if (b_sq == b * b) {
+            cat (n, b, c, "\n")
+        }
+
+        c_sq <- c_sq + 2 * c + 1
+        c    <- c + 1
+    }
+
+    max_a = floor (n / sqrt (2))
+    if (max_a < 3) {
+        next
+    }
+    for (a in 3 : max_a) {
+      # cat ("a = ", a, "\n")
+        b_sq <- n_sq - a * a
+        b    <- introot (b_sq)
+
+        if (b_sq == b * b) {
+            cat (a, b, n, "\n")
+        }
+    }
+}