PremiumFriday.kt

import java.time.*
import java.time.format.*
import java.time.temporal.*

fun main(args: Array<String>) {
    val formatter = DateTimeFormatter.ofPattern("yyyy/MM/dd(E)")
    (2017..2020).flatMap { year -> Month.values().map { month -> YearMonth.of(year, month) } }
        .filterNot { it.year == 2017 && it.month == Month.JANUARY }
        .map(YearMonth::atEndOfMonth)
        .map { ymd -> ymd.with(TemporalAdjusters.lastInMonth(DayOfWeek.FRIDAY)) }
        .map(formatter::format)
        .forEach(::println)
}