answer:The ratio of 52nd to 28th term is exactly 4. This is the only real clue here. This suggests a geometric series, in which case the terms quadruple every 52 – 28 = 24 positions, or double every 12. This is exactly the case with the well-tempered piano scale, where frequencies double each octave of 12 semi-tones. The ratio between successive terms is the twelfth root of two, which is 2^(1/12) = 1.059… (Each note is about 6 percent higher in frequency than its predecessor). What puzzles me is that the numbers in your sequence are on the order of a million times bigger than piano frequencies in cycles per second (Hertz).