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%I #16 Apr 20 2021 07:46:29
%S 8,9,9,10,10,11,12,12,13,14,15,15,16,17,18,19,21,22,23,24,26,28,29,31,
%T 33,35,37,39,41,44,46,49,52,55,58,62,65,69,73,78,82,87,92,98,104,110,
%U 117,123,131,139,147,156,165,175,185,196,208,220,233,247,262,277,294,311
%N a(n) is the frequency of MIDI note number n in Hertz, rounded to the nearest integer.
%C In electronic music, pitch is often given by MIDI note number. The MIDI number of A_4 (440 Hz) is 69; if a note is k semitones higher than A_4, its MIDI note number is 69 + k, and its frequency is 440*2^(k/12) Hz.
%C Note that audible notes have MIDI note numbers 16 (20.6017 Hz) to 135 (19912.1270 Hz).
%H Jianing Song, <a href="/A320304/b320304.txt">Table of n, a(n) for n = 0..1023</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Scientific_pitch_notation#Table_of_note_frequencies ">Table of note frequencies</a>
%F a(n) = round(6.875*2^(n/12+1/4)).
%e MIDI note | Note name | Frequency
%e number | | (Hz)
%e 0 | C_{-1} | 8.1758
%e 1 | C#_{-1} | 8.6620
%e 2 | D_{-1} | 9.1770
%e 3 | D#_{-1} | 9.7227
%e 4 | E_{-1} | 10.3009
%e 5 | F_{-1} | 10.9134
%e 6 | F#_{-1} | 11.5623
%e 7 | G_{-1} | 12.2499
%e 8 | G#_{-1} | 12.9782
%e 9 | A_{-1} | 13.7500
%e 10 | A#_{-1} | 14.5676
%e 11 | B_{-1} | 15.4339
%e 12 | C_{0} | 16.3516
%o (PARI) a(n) = round(6.875*2^(n/12+1/4))
%Y Cf. A144488.
%K nonn,easy
%O 0,1
%A _Jianing Song_, Oct 10 2018
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