A331425 - OEIS

A331425

Divide each side of a triangle into 2*n (n>=1) equal parts and trace the corresponding cevians, i.e., join every point, except for the first and last ones, with the opposite vertex. a(n) is the number of points at which three cevians meet.

1, 7, 13, 19, 25, 31, 37, 43, 49, 61, 61, 91, 73, 79, 91, 91, 97, 103, 109, 133, 133, 127, 133, 187, 145, 151, 157, 175, 169, 235, 181, 187, 205, 199, 229, 283, 217, 223, 235, 325, 241, 283, 253, 271, 331, 271, 277, 343, 289, 301, 301, 319, 313, 319, 349, 439

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

OFFSET

1,2

COMMENTS

A bisection of A331423.

LINKS

Table of n, a(n) for n=1..56.

FORMULA

a(n) = A331423(2*n).

MATHEMATICA

CevIntersections[n_] := Length[Solve[(n - i)*(n - j)*(n - k) - i*j*k == 0 && 0 < i < n && 0 < j < n && 0 < k < n, {i, j, k}, Integers]];

Map[CevIntersections[#] &, Range[2, 50, 2]]