JP Journal of Algebra, Number Theory and Applications

The JP Journal of Algebra, Number Theory and Applications is a prestigious international journal indexed in the Emerging Sources Citation Index (ESCI). It publishes original research papers, both theoretical and applied in nature, in various branches of algebra and number theory. The journal also welcomes survey articles that contribute to the advancement of these fields.

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AN INTEGER SEQUENCE WHICH IS THE SUM OF TRIANGULAR NUMBERS AND EXTRA NUMBERS

Authors

  • Yasuhiko Kamiyama

Keywords:

integer sequence, triangular number

DOI:

https://doi.org/10.17654/0972555525030

Abstract

We fix a positive integer $n$. For each positive integer $k$, we define $X(n, k)$ to be set consisting of the pair of integers $(a, b)$ which satisfies $a^2+b^2=k$ and $1 \leq a<b \leq n$. Let $|X(n, k)|$ be the cardinality of $X(n, k)$ and we define $P(n)$ to be the sum of $|X(n, k)|^2$ over $k$. In this paper, we study the properties of the integer sequence $P(n)$.

Received: May 29, 2025
Accepted: July 28, 2025

References

[1] Y. Kamiyama, The Euler characteristic of the fiber product of Morse functions, Bull. Korean Math. Soc. 62 (2025), 71-80.

[2] Mathematica 11.3, Wolfram Research, Champaign, IL, 2018.

[3] J. Milnor, Morse theory, Based on lecture notes by M. Spivak and R. Wells. Annals of Mathematics Studies, 51, Princeton University Press, Princeton, NJ, 1963.

[4] J. Milnor and J. Stasheff, Characteristic classes, Annals of Mathematics Studies, 76, Princeton University Press, Princeton, NJ, 1974.

[5] N. J. A. Sloane, On-Line Encyclopedia of Integer Sequences, Sequence #A125806: https://oeis.org/A125806.

[6] N. J. A. Sloane, On-Line Encyclopedia of Integer Sequences, Sequence #A374020: https://oeis.org/A374020.

[7] T. Sugawara, A construction of Morse functions on flag manifolds, Mem. Fac. Sci. Kyushu Univ. 34(1) (1980), 107-125.

[8] TuringBot, Symbolic Regression Software, 2020. https://turingbotsoftware.com.

Published

2025-08-28

Issue

Section

Articles

How to Cite

AN INTEGER SEQUENCE WHICH IS THE SUM OF TRIANGULAR NUMBERS AND EXTRA NUMBERS. (2025). JP Journal of Algebra, Number Theory and Applications, 64(5), 575-583. https://doi.org/10.17654/0972555525030

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