Voozh

A341740

a(n) is the maximum value of the magic constant in a normal magic triangle of order n.

12, 23, 37, 54, 74, 97, 123, 152, 184, 219, 257, 298, 342, 389, 439, 492, 548, 607, 669, 734, 802, 873, 947, 1024, 1104, 1187, 1273, 1362, 1454, 1549, 1647, 1748, 1852, 1959, 2069, 2182, 2298, 2417, 2539, 2664, 2792, 2923, 3057, 3194, 3334, 3477, 3623, 3772, 3924

(list; graph; refs; listen; history; text; internal format)

OFFSET

3,1

LINKS

Table of n, a(n) for n=3..51.

Terrel Trotter, Normal Magic Triangles of Order n, Journal of Recreational Mathematics Vol. 5, No. 1, 1972, pp. 28-32.

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

O.g.f.: x^3*(12 - 13*x + 4*x^2)/(1 - x)^3.

E.g.f.: 3 + x - 2*x^2 - exp(x)*(6 - 4*x - 3*x^2)/2.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 5.

a(n) = (3*n^2 + n - 6)/2 for n > 2.