My question is so basic, I'm embarrassed to ask it. (I study computational theory, not economics.) I'm looking at quarterly GDP numbers and growth rates. I've tried to arrive at the BEA's CPGDPAI numbers using the generic formula:
GDP(t)/GDP(t-1) = (1 + r)^t - t-1
Which fails miserably. I'm grateful for some light on this.
So, it's the data, not the math. I was pulling the nominal GDP data off FRED. After plugging in the the GDPC1 data, it was all right as rain. A rookie mistake, but, well, I'm a rookie. Thanks for the answers below.