diff --git a/cmd/convergents.go b/cmd/convergents.go
index c5863ef..b7cf9d1 100644
--- a/cmd/convergents.go
+++ b/cmd/convergents.go
@@ -23,14 +23,14 @@ import (
 	"github.com/spf13/cobra"
 )
 
-func cycle(seq []*big.Int, ch chan *big.Int) {
+func cycle(seq []*big.Int, ch chan<- *big.Int) {
 	n := len(seq)
 	for i := 0; true; i = (i + 1) % n {
 		ch <- seq[i]
 	}
 }
 
-func gaussianBrackets(x, xprev *big.Int, seq []*big.Int, ch chan *big.Int) {
+func gaussianBrackets(x, xprev *big.Int, seq []*big.Int, ch chan<- *big.Int) {
 	c := make(chan *big.Int)
 	go cycle(seq, c)
 	for a := range c {