diff --git a/src/syntax.c b/src/syntax.c
index 788a9f5..aee2d6a 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -311,7 +311,7 @@
 				       but contained groups */
 
 #ifdef FEAT_CONCEAL
-static int next_seqnr = 0;		/* value to use for si_seqnr */
+static int next_seqnr = 1;		/* value to use for si_seqnr */
 #endif
 
 /*