diff --git a/solutions/c/grains/1/grains.c b/solutions/c/grains/1/grains.c
new file mode 100644
index 0000000..e2c07b7
--- /dev/null
+++ b/solutions/c/grains/1/grains.c
@@ -0,0 +1,20 @@
+#include "grains.h"
+
+uint64_t square(uint8_t index)
+{
+    if (index == 1)
+        return 1;
+    return (2 * square(index - 1));
+}
+
+uint64_t total(void)
+{
+    /*
+    S_n = 1 + 2 + 4 + ... + 2^n
+    S_n * 2 = 2 + 4 + ... + 2^(n + 1) 
+    --> S_n = 2^(n + 1) - 1
+    so S_64 = 1 + 2 + 4 + ... + 2^64 = 2^(65) - 1
+    */
+    
+    return (square(65) - 1);
+}
\ No newline at end of file
diff --git a/solutions/c/grains/1/grains.h b/solutions/c/grains/1/grains.h
new file mode 100644
index 0000000..ed53556
--- /dev/null
+++ b/solutions/c/grains/1/grains.h
@@ -0,0 +1,9 @@
+#ifndef GRAINS_H
+#define GRAINS_H
+
+#include <stdint.h>
+
+uint64_t square(uint8_t index);
+uint64_t total(void);
+
+#endif