p">(</span><span class="fl">2</span><span class="op">*</span><span class="va">I</span><span class="op">+</span><span class="fl">1</span>,<span class="fl">3</span><span class="op">*</span><span class="va">I</span><span class="op">)</span><span class="op">]</span> <span class="op">&lt;-</span> <span class="fl">1</span><span class="op">:</span><span class="va">I</span></span>
<span><span class="va">mod2</span> <span class="op">&lt;-</span> <span class="fu">sirt</span><span class="fu">::</span><span class="fu">