The Triangular Moving Average (TMA) is similar to other moving averages (exponential and weighted) except it uses a different weighting scheme. Exponential and weighted moving averages assign the majority of the weight to the most recent data. Simple moving averages assign the weight equally across all the data. With a triangular moving average, it is double smoother (it is averaged twice) so the majority of the weight is assigned to the middle portion of the data.
The triangular moving average (TMA) is a weighted average of the last n prices (P), whose result is equivalent to a double-smoothed simple moving average:
SMA = (P1 + P2 + P3 + P4 + ... + Pn) / n
TMA = (SMA1 + SMA2 + SMA3 + SMA4 + ... SMAn) / n