A342467 a(n) is the number of n-th order magic triangles.

0, 4, 18, 700, 13123, 316424, 7317145, 176476738, 4279366371

Offset: 2

Author

Stefano Spezia, Mar 13 2021

Keywords

• nonn
• more

Comments

The Trotter reference gives the value 1356 = 76 * 18 for a(5), which is incorrect since 76 is the number of corner groupings and 18 is the maximum number of solutions in any grouping. - Andrew Howroyd, Feb 05 2022

Links

• Andrew Howroyd, PARI Program, Feb 2022.
• Terrel Trotter, Normal Magic Triangles of Order n, Journal of Recreational Mathematics Vol. 5, No. 1, 1972, pp. 28-32.
• Terrel Trotter, Perimeter-Magic Polygons, Journal of Recreational Mathematics Vol. 7, No. 1, 1974, pp. 14-20.

Crossrefs

Row sums of A342384.

Cf. A016777, A179805, A285009, A341740, A351223.

Programs

PARI

\\ See Links.

Formula

a(n) < A351223(n). - Stefano Spezia, Feb 05 2022

Extensions

a(5) corrected by Andrew Howroyd and Stefano Spezia, Feb 05 2022

a(6)-a(10) from Andrew Howroyd, Feb 05 2022