penny doubled each day for a month:

day 1: $0.01
day 2: $0.02
day 3: $0.04
day 4: $0.08
day 5: $0.16
day 6: $0.32
day 7: $0.64
day 8: $1.28
day 9: $2.56
day 10: $5.12
day 11: $10.24
day 12: $20.48
day 13: $40.96
day 14: $81.92
day 15: $163.84
day 16: $327.68
day 17: $655.36
day 18: $1,310.72
day 19: $2,621.44
day 20: $5,242.88
day 21: $10,485.76
day 22: $20,971.52
day 23: $41,943.04
day 24: $83,886.08
day 25: $167,772.16
day 26: $335,544.32
day 27: $671,088.64
day 28: $1,342,177.28
day 29: $2,684,354.56
day 30: $5,368,709.12
day 31: $10,737,418.23

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