Each of x and y is a positive integer that satisfies this equation:
x^oC=y^oF

Determine the minimum value of x+y such that:
x is a triangular number and, y is a heptagonal pyramidal number.
What is the next smallest value of x+y?

*** ^oF = (9/5)*^oC+32, where ^oF represents degree Fahrenheit and, ^oC represents degree Celsius.