A001213 a(n) is the solution to the postage stamp problem with n denominations and 3 stamps.

3, 7, 15, 24, 36, 52, 70, 93, 121, 154, 186, 225, 271, 323, 385, 450, 515, 606, 684, 788, 865, 977, 1091, 1201, 1361

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• more

Comments

Fred Lunnon [W. F. Lunnon] defines "solution" to be the smallest value not obtainable by the best set of stamps. The solutions given are one lower than this, that is, the sequence gives the largest number obtainable without a break using the best set of stamps.

References

• R. K. Guy, Unsolved Problems in Number Theory, C12.
• N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, 87 (1980), 206-210.
• Erich Friedman, Postage stamp problem
• R. L. Graham and N. J. A. Sloane, On Additive Bases and Harmonious Graphs, SIAM J. Algebraic and Discrete Methods, 1 (1980), 382-404.
• R. L. Graham and N. J. A. Sloane, On Additive Bases and Harmonious Graphs
• W. F. Lunnon, A postage stamp problem, Comput. J. 12 (1969) 377-380.
• Eric Weisstein's World of Mathematics, Postage stamp problem

Crossrefs

Postage stamp sequences: A001208, A001209, A001210, A001211, A001212, A001213, A001214, A001215, A001216, A005342, A005343, A005344, A014616, A053346, A053348, A075060, A084192, A084193.

A row or column of the array A196416 (possibly with 1 subtracted from it).

Extensions

Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004

More terms from Al Zimmermann, Feb 20 2002

Further terms from Friedman web site, Jun 20 2003

Incorrect value of a(17) removed by Al Zimmermann, Nov 08 2009

a(17)-a(25) from Friedman added by Robert Price, Jul 19 2013