Ancient Greek mathematicians called 1, 3, 6, 10, 15, ... triangular numbers, what is the difference between the 16th triangular number and the 14th triangular number
古希腊数学家把1，3，6，10，15，…叫做三角形数，则第16个三角形数与第14个三角形数的差是多少
<gadget id="calculator">16 + 1</gadget>
<output>17</output>

<gadget id="calculator">16 * 17</gadget>
<output>272</output>

<gadget id="calculator">272 / 2</gadget>
<output>136</output>

<gadget id="calculator">14 + 1</gadget>
<output>15</output>

<gadget id="calculator">14 * 15</gadget>
<output>210</output>

<gadget id="calculator">210 / 2</gadget>
<output>105</output>

<gadget id="calculator">136 - 105</gadget>
<output>31</output>

<result>31</result>