AWS SDK for .NET Documentation
Recurrence Property
AmazonAmazon.AutoScaling.ModelPutScheduledUpdateGroupActionRequestRecurrence Did this page help you?   Yes   No    Tell us about it...
The time when recurring future actions will start. Start time is specified by the user following the Unix cron syntax format. For information about cron syntax, go to Wikipedia, The Free Encyclopedia. When StartTime and EndTime are specified with Recurrence, they form the boundaries of when the recurring action will start and stop.

Constraints:

Length
1 - 255
Pattern
[\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Declaration Syntax
C#
public string Recurrence { get; set; }

Assembly: AWSSDK (Module: AWSSDK) Version: 1.5.60.0 (1.5.60.0)