This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A329215 #15 Jun 19 2024 03:05:23 %S A329215 4,1,5,3,0,4,6,9,7,5,7,9,9,4,5,1,3,8,5,2,2,4,4,1,7,8,8,9,3,3,7,1,5,1, %T A329215 2,5,4,4,3,3,3,0,0,5,3,4,6,9,0,4,6,8,3,8,0,4,6,5,3,5,0,6,2,6,2,0,0,4, %U A329215 6,0,5,4,6,0,5,0,3,0,9,4,9,3,3,9,8,8,7,3,2,0,0 %N A329215 Decimal expansion of the fundamental frequency of the note G#4/Ab4 in hertz. %C A329215 In 12-tone equal temperament, when A4 (the fifth A on the Piano keyboard) is tuned to 440 Hz, the frequency of the note G#4/Ab4 (1 semitone below A4) is 440*2^(-1/12) Hz = 415.3 Hz. %H A329215 Wikipedia, <a href="https://en.wikipedia.org/wiki/Piano_key_frequencies">Piano key frequencies</a> %H A329215 <a href="/index/Mu#music">Index entries for sequences based on music</a> %H A329215 <a href="/index/Al#algebraic_12">Index entries for algebraic numbers, degree 12</a> %F A329215 Equals 220 * 2^(11/12). %e A329215 Frequencies of notes in an octave (Hz): %e A329215 >-------------------------------------------------- %e A329215 | %e A329215 | C4 261.6255653005... (A329207) %e A329215 | +--------------------------------------- %e A329215 >----------| C#4/Db4 277.1826309768... (A329208) %e A329215 | +--------------------------------------- %e A329215 | D4 293.6647679174... (A329209) %e A329215 | +--------------------------------------- %e A329215 >----------| D#4/Eb4 311.1269837220... (A329210) %e A329215 | +--------------------------------------- %e A329215 | E4 329.6275569128... (A329211) %e A329215 | %e A329215 >-------------------------------------------------- %e A329215 | %e A329215 | F4 349.2282314330... (A329212) %e A329215 | +--------------------------------------- %e A329215 >----------| F#4/Gb4 369.9944227116... (A329213) %e A329215 | +--------------------------------------- %e A329215 | G4 391.9954359817... (A329214) %e A329215 | +--------------------------------------- %e A329215 >----------| G#4/Ab4 415.3046975799... (this seq) %e A329215 | +--------------------------------------- %e A329215 | A4 440.0000000000 %e A329215 | +--------------------------------------- %e A329215 >----------| A#4/Bb4 466.1637615180... (A329217) %e A329215 | +--------------------------------------- %e A329215 | B4 493.8833012561... (A329218) %e A329215 | %e A329215 >-------------------------------------------------- %e A329215 [New layout from _Jon E. Schoenfield_, Nov 08 2019] %t A329215 First[RealDigits[220*2^(11/12), 10, 100]] (* _Paolo Xausa_, Jun 18 2024 *) %o A329215 (PARI) default(realprecision, 100); 440 * 2^(-1/12) %Y A329215 See the Example section above for the fundamental frequency of some other notes. %K A329215 nonn,easy,cons %O A329215 3,1 %A A329215 _Jianing Song_, Nov 08 2019