code: def eulernum(ctx, n, exact=False):
      n = int(n)
      if exact:
          return int(ctx._eulernum(n))
      if n < 100:
          return ctx.mpf(ctx._eulernum(n))
      if n % 2:
          return ctx.zero
      return ctx.ldexp(ctx.eulerpoly(n, 0.5), n)
  
imports: from __future__ import print_function
  from ..libmp.backend import xrange
  from .functions import defun, defun_wrapped, defun_static
label_desc: Use image node_id 13 for calling a global function with example usage: eulernum(ctx, n, exact) and returns: ctx, int, ctx, ctx