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Peak numbers

Published online by Cambridge University Press:  01 August 2016

Tabitha T. Y. Mingus  and
Richard Grassl
Tabitha T. Y. Mingus
Affiliation:
Department of Mathematics and Statistics, Western Michigan University, Kalamazoo, MI 49008 USA
Richard Grassl
Affiliation:
Department of Mathematical Sciences, University of Northern Colorado, Greeley, CO 80639 USA
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Extract

Two recent problems appearing in die September 1997 and September 1999 issues of the NCTM publication Mathematics Teacher asked the following:

A. An integer is called decreasing if each digit is less than the one to its left. Determine the number of decreasing integers between 2000 and 7000.

B. A 5-digit integer is a peak number if its digits strictly increase to the middle one then strictly descend. Determine the number of 5-digit peak numbers that are greater than 70,000.

Type
Articles
Information
The Mathematical Gazette , Volume 86 , Issue 505 , March 2002 , pp. 44 - 50
Copyright
Copyright © The Mathematical Association 2002

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References

1. Grassl, R. The squares do fit!, Math. Gaz. 79 (July 1995) pp. 361–364.CrossRefGoogle Scholar
2. Anderson, I. Sums and squares of binomial coefficients, Math. Gaz. 65 (June 1981), pp. 87–92.CrossRefGoogle Scholar
3. Singmaster, D. Sums of squares and pyramid numbers, Math. Gaz. 66 (June 1982), pp. 100–104.CrossRefGoogle Scholar
4. Petkovsek, M. Wilf, H. Zeilberger, D. A = B, A. K. Peters (1996).CrossRefGoogle Scholar
5. Grassl, R. Mingus, T. Keep counting those boxes – there’s more, Mathematics Teacher 91 (February 1998) pp. 122–127.CrossRefGoogle Scholar