different display methods give different results

edit

when evaluating the following code we get 2 different results even tho the same expressions are being evaluated:

  %display plain
  k,n = var('k,n')
  s = n/2 * sum(3/(n+k)^2, k, 1, n)
  s.limit(n=Infinity)
  %display unicode_art
  k,n = var('k,n')
  s = n/2 * sum(3/(n+k)^2, k, 1, n)
  s.limit(n=Infinity)

whats going on here? why the inconsistency?