A114139 Changes in United States postal rates per ounce since 1863.
-2, -2, 1, -1, 1, 1, 1, 1, 2, 2, 0, 3, 2, 3, 2, 2, 3, 4, 3, 3, 1, 1, 3, 2
Offset: 1
Examples
a(1) = -2 because the rate per half ounce was lowered effective 3 March 1863 from 3 cents to 2 cents; thereafter rates were per ounce.
References
- R. K. Guy, Unsolved Problems in Number Theory, C12.
Links
- R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, Vol. 87, No. 3 (1980), 206-210.
- A. K. Dart, The History of Postage Rates in the United States
- W. F. Lunnon, A postage stamp problem, Comput. J., Vol. 12, No. 4 (1969) 377-380.
- USPS, Benjamin Franklin Commemorative Stamps
- 1847usa.com, United States Postage Stamps By Year.
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