diff --git a/lib/srfi/151/bit.c b/lib/srfi/151/bit.c
index 45254b64..a02e90bd 100644
--- a/lib/srfi/151/bit.c
+++ b/lib/srfi/151/bit.c
@@ -350,7 +350,7 @@ static const char log_table_256[256] =
 {
 #define LT(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
   0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
-  LT(5), LT(6), LT(7), LT(7), LT(7), LT(7), LT(7),
+  LT(5), LT(6), LT(6), LT(7), LT(7), LT(7), LT(7),
   LT(8), LT(8), LT(8), LT(8), LT(8), LT(8), LT(8), LT(8)
 };
 
diff --git a/lib/srfi/151/test.sld b/lib/srfi/151/test.sld
index 4c59a03f..92fd6782 100644
--- a/lib/srfi/151/test.sld
+++ b/lib/srfi/151/test.sld
@@ -5,6 +5,13 @@
     (define (run-tests)
       (test-begin "srfi-151: bitwise operations")
 
+      (test 0 (integer-length #b0))
+      (test 1 (integer-length #b1))
+      (test 2 (integer-length #b10))
+      (test 3 (integer-length #b100))
+      (test 4 (integer-length #b1000))
+      (test 5 (integer-length #b10000))
+      (test 6 (integer-length #b110000))
       (test 0 (bitwise-and #b0 #b1))
       (test 1 (bitwise-and #b1 #b1))
       (test 0 (bitwise-and #b1 #b10))