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URL: https://oeis.org/A341740

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A341740
a(n) is the maximum value of the magic constant in a normal magic triangle of order n.
3
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
OFFSET
3,1
LINKS
Terrel Trotter, Normal Magic Triangles of Order n, Journal of Recreational Mathematics Vol. 5, No. 1, 1972, pp. 28-32.
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.
a(n) = A285009(n) + A016777(n-2) - 1 for n > 3.
a(n) = A095794(n) - 2 = A140090(n-1) - 1. - Hugo Pfoertner, Feb 18 2021
MATHEMATICA
LinearRecurrence[{3, -3, 1}, {12, 23, 37}, 49]
KEYWORD
nonn,easy
AUTHOR
Stefano Spezia, Feb 18 2021
STATUS
approved