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A001209 a(n) = solution to the postage stamp problem with 4 denominations and n stamps.
(Formerly M3432 N1568)
25
4, 12, 24, 44, 71, 114, 165, 234, 326, 427, 547, 708, 873, 1094, 1383, 1650, 1935, 2304, 2782, 3324, 3812, 4368, 5130, 5892, 6745, 7880, 8913, 9919, 11081, 12376, 13932, 15657, 17242, 18892, 21061, 23445, 25553, 27978, 31347, 33981, 36806, 39914, 43592 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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.

Challis lists up to a(54) and provides recursions up to a(157). - R. J. Mathar, Apr 01 2006

Additional terms a(29) through a(254) can be computed using 3 sets of equations and a table of 10 coefficients available on line at Challis and Robinson. [John P Robinson (john-robinson(AT)uiowa.edu), Feb 18 2010]

REFERENCES

R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, 87 (1980), 206-210.

R. K. Guy, Unsolved Problems in Number Theory, C12.

W. F. Lunnon, A postage stamp problem. Comput. J. 12 (1969) 377-380.

S. Mossige, Algorithms for Computing the h-Range of the Postage Stamp Problem, Math. Comp. 36 (1981) 575-582

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

Robert Price, Table of n, a(n) for n = 1..54

M. F. Challis, Two new techniques for computing extremal h-bases A_k, Comp. J. 36(2) (1993) 117-126

M. F. Challis and J. P. Robinson, Some Extremal Postage Stamp Bases, J. Integer Seq., 13 (2010), Article 10.2.3.

Erich Friedman, Postage stamp problem

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.

Equals A196069 - 1.

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

Sequence in context: A011887 A057305 A008195 * A227587 A128624 A192797

Adjacent sequences:  A001206 A001207 A001208 * A001210 A001211 A001212

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

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

Added a(15) to a(28) from Table 1 of Mossige reference. - R. J. Mathar, Mar 29 2006

a(29)-a(54) from Challis and Robinson by Robert Price, Jul 19 2013

STATUS

approved

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Last modified April 23 18:45 EDT 2017. Contains 285329 sequences.