# Load the lubridate package for date manipulation
library(lubridate)

# Create a sequence of date-time values every 30 minutes for 4 days
start_date <- as.POSIXct('1995-06-30 00:00:00', tz = "UTC")
end_date <- start_date + days(4) - minutes(30)
date_seq <- seq(from = start_date, to = end_date, by = "30 min")

# Calculate temperature values following a sine curve
temperature <- 265.15 + 20 * sin(2 * pi * (hour(date_seq) + minute(date_seq)/60) / 24)

# Create a data frame
data <- data.frame(Date = date_seq, Temperature_K = temperature)

# Format the Date column
data$Date <- format(data$Date, format = '%d/%m/%Y %H:%M')

# Save the data to a CSV file
write.csv(data, file = "time_series_data.csv", row.names = FALSE)

cat("CSV file 'time_series_data.csv' has been created.")