cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A268855 a(n) = smallest magic sum of any 3 X 3 magic square which contains exactly n squares.

Original entry on oeis.org

30, 21, 18, 15, 39, 120, 435, 541875
Offset: 0

Views

Author

Arkadiusz Wesolowski, Feb 14 2016

Keywords

Comments

a(7) = 8*A268854(7) + 3.
If a(8) exists, and the central element is a square, then a(8) > 10^21. - Arkadiusz Wesolowski, Sep 01 2024

Crossrefs

A268856 a(n) = smallest magic sum of any 3 X 3 magic square which contains exactly n numbers that are triangular or square.

Original entry on oeis.org

39, 36, 30, 21, 21, 15, 27, 675
Offset: 0

Views

Author

Arkadiusz Wesolowski, Feb 14 2016

Keywords

Comments

a(8) and a(9) are greater than 10^10. - Arkadiusz Wesolowski, Oct 27 2018
a(8) <= 3*7215727335550^2 = (A221669(1) + A221669(2) + A221669(3))*16978181966^2. - Arkadiusz Wesolowski, May 21 2022

Crossrefs

A268854 a(n) is the smallest magic sum of any 3 X 3 magic square which contains exactly n triangular numbers.

Original entry on oeis.org

39, 24, 21, 15, 18, 24, 189, 67734
Offset: 0

Views

Author

Arkadiusz Wesolowski, Feb 14 2016

Keywords

Crossrefs

A271450 a(n) = smallest magic sum of any 3 X 3 magic square which contains exactly n cubes, or 0 if no such magic square exists.

Original entry on oeis.org

27, 18, 15, 42, 882
Offset: 0

Views

Author

Arkadiusz Wesolowski, Apr 14 2016

Keywords

Comments

For n >= 7, a(n) = 0 because the equation x^n + y^n = 2*z^n has no solution for n > 2 apart from the trivial x = y = z.

References

  • Richard K. Guy, Unsolved Problems in Number Theory, New York: Springer-Verlag, 2004, pp. 268-271.

Crossrefs

Cf. A269231.
Showing 1-4 of 4 results.