A001212 a(n) = solution to the postage stamp problem with n denominations and 2 stamps.
2, 4, 8, 12, 16, 20, 26, 32, 40, 46, 54, 64, 72, 80, 92, 104, 116, 128, 140, 152, 164, 180, 196, 212
Offset: 1
References
- Gardner, M. The Sixth Book of Mathematical Games from Scientific American. Chicago, IL: University of Chicago Press, p. 115 (Coins of the Realm), 1984.
- 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, Letter to N. J. A. Sloane, Mar 25 1977
- R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, 87 (1980), 206-210.
- 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
- 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
- F. H. Kierstead, Jr.,, The Stamp Problem, J. Rec. Math., Vol. ?, Year ?, page 298. [Annotated and scanned copy]
- J. Kohonen, A meet-in-the-middle algorithm for finding extremal restricted additive 2-bases, arXiv preprint arXiv:1403.5945, 2014 and J. Int. Seq. 17 (2014) # 14.6.8.
- J. Kohonen, J. Corander, Addition Chains Meet Postage Stamps: Reducing the Number of Multiplications, J. Integer Seq., 17 (2014), Article 14.3.4.
- J. Kohonen, Early Pruning in the Restricted Postage Stamp Problem, arXiv preprint arXiv:1503.03416, 2015
- W. F. Lunnon, A postage stamp problem, Comput. J. 12 (1969) 377-380.
- W. F. Lunnon, A postage stamp problem [Annotated scanned copy]
- J. P. Robinson, Some postage stamp 2-bases, JIS 12 (2009) 09.1.1.
- E. S. Selmer, Letter to N. J. A. Sloane, Sep 10 1991
- Eric Weisstein's World of Mathematics, Postage stamp problem
- Mingjia Yang, An experimental walk in patterns, partitions, and words, Ph. D. Dissertation, Rutgers University (2020).
Crossrefs
Extensions
Corrected a(17). Added a(18) and a(19) from Challis. - R. J. Mathar, Apr 01 2006
Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004
a(20) from Tim Peters (tim.one(AT)comcast.net), Oct 04 2006
Added terms a(21) and a(22) from Challis and Robinson. John P Robinson (john-robinson(AT)uiowa.edu), Feb 19 2010
Added term a(23) from Challis and Robinson's July 2013 addendum, by Jukka Kohonen, Oct 25 2013
Added a(24) from Kohonen and Corander (2013). - N. J. A. Sloane, Jan 08 2014
Comments