A219326 Positive integers m that are equal to the determinant of the circulant matrix formed by the decimal digits of m in reverse order.

1, 2, 3, 4, 5, 6, 7, 8, 9, 48, 247, 370, 378, 407, 481, 518, 592, 629, 1547, 26027, 26933, 45018, 69781, 80487, 123823, 289835, 1920261, 2137616, 2716713, 3100883, 3480140, 3934896, 4179451, 4830936, 5218958, 23203827

Offset: 1

Author

Max Alekseyev, Nov 17 2012

Keywords

• base
• nonn

Comments

Terms with odd number of digits are the same as in A219324.

Examples

			           | 7 4 5 1 |
1547 = det | 1 7 4 5 |
           | 5 1 7 4 |
           | 4 5 1 7 |
		

Links

• Max Alekseyev, Table of n, a(n) for n = 1..53 (complete up to 10^10)

Crossrefs

A219324 is the main entry for this sequence, provides references and further details.

Programs

Python

from sympy import Matrix
A219326_list = []
for n in range(1,10**6):
    s = [int(d) for d in str(n)][::-1]
    m = len(s)
    if n == Matrix(m, m, lambda i, j: s[(i-j) % m]).det():
        A219326_list.append(n) # Chai Wah Wu, Oct 18 2021