Days of the year which are powers of 2 starting from both beginning and end of the year.

dates.go

package main

import (
	"fmt"
	"time"
)

const (
	DateFormat = "2006-01-02: Jan 02"
)

func main() {
	day := 24 * time.Hour
	
	forwardDate := time.Date(2012, 1, 1, 0, 0, 0, 0, time.FixedZone("America/Denver", -6))
	reverseDate := time.Date(2013, 1, 1, 0, 0, 0, 0, time.FixedZone("America/Denver", -6))
	
	for i := 1; i < 356; i <<= 1 {
		forward := forwardDate.Add(time.Duration(i) * day)
		reverse := reverseDate.Add(-time.Duration(i) * day)
		fmt.Printf("% 4d: %+v\t%+v\n", i, forward.Format(DateFormat), reverse.Format(DateFormat))
	}
}