hworld.wolfram.com/TangentNumber.html" target="_top">Tangent
        number</a>.
      </p>
<p>
        The first few values are 1, 2, 16, 272, 7936, 353792, 22368256, 1903757312
        ... (sequence <a href="http://oeis.org/A000182" target="_top">A000182 in OEIS</a>).
        They are called tangent numbers because they appear as numerators in the
        Maclaurin series of <code class="computeroutput"><span class="identifier">tan</span><span class="special">(</span><span class="identifier">x</span><span