Happy Numbers and Fixed Points
DOI:
https://doi.org/10.35819/remat2023v9i1id6190Keywords:
Happy Numbers, Fixed Points, Sequence of IntegersAbstract
This paper presents a brief study about the set of happy numbers, in any positional basis b>=2. We show examples of happy numbers and verify that every positive integer is happy in basis 4, Example 2.8. In particular, we characterize the fixed points of the happiness function, Theorem 3.2, which assigns to every positive integer the sum of the squares of its digits. In addition, techniques to determine the fixed points of the happiness function are showed, Theorem 3.5, Examples 3.7 and 3.8, in any positional basis.
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BEARDON, A. F. Sums of squares of digits. The Mathematical Gazette. v. 82, p. 379-388, 1998.
EL-SEDY, E.; SIKSEK, S. On Happy Numbers. Rocky Mountain Journal of Mathematics. v. 30, n. 2, p. 565-570, 2000. DOI: www.doi.org/10.1216/rmjm/1022009281.
GARCIA, A.; LEQUAIN, Yves. Elementos de Álgebra. 6. ed. Rio de Janeiro: IMPA, 2018.
GRUDMAN, H. G.; TEEPLE, E. A. Generalized Happy Numbers. The Fibonacci Quarterly. p. 462-466, 2001. Disponível em: https://www.fq.math.ca/Scanned/39-5/grundman.pdf. Acesso em: 22 jan. 2023.
GUY, R. Unsolved Problems in Number Theory. 3. ed. New York: Springer-Verlag, 2004.
HEFEZ, A. Aritmética. 2. ed. Rio de Janeiro: Coleção PROFMAT, SBM, 2016.
MUTTER, S. A. Happy Numbers: An Exploration of An Iterated Function in Different Bases. A Senior Project submitted to The Division of Science, Mathematics, and Computing of Bard College, 2010. Disponível em: https://media.gradebuddy.com/documents/1849233/5193b459-c8ea-46a9-a583-580895ca1a7e.pdf. Acesso em: 21 fev. 2023.
PAN, H. On consecutive happy numbers. Journal of Number Theory. v. 128, n. 6, p. 1646-1654, jun. 2008. DOI: www.doi.org/10.1016/j.jnt.2007.11.009.
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