I used range(row \* (row - 1) // 2 \* n + col, row \* (row + 1) // 2 \* n + col,...

I used range(row * (row - 1) // 2 * n + col, row * (row + 1) // 2 * n + col, row) in Python. For n = 14, row = 13, col = 3, this is

[1095, 1108, 1121, 1134, 1147, 1160, 1173, 1186, 1199, 1212, 1225, 1238, 1251, 1264]

none of which are prime. cellToTerms(13, 14, binomialCoEfficient2, 3) in the observable gives the same list (though no such calls are made when generating the picture).