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 A329212 #12 Aug 21 2023 11:14:40 %S A329212 3,4,9,2,2,8,2,3,1,4,3,3,0,0,3,8,8,4,4,4,5,3,7,5,2,4,0,6,3,9,9,0,7,8, %T A329212 1,7,2,8,6,1,2,8,5,3,2,1,3,7,9,6,7,6,6,2,1,5,7,8,2,2,8,6,7,6,0,1,5,4, %U A329212 7,6,3,1,2,3,7,3,2,8,2,1,8,1,2,0,1,7,9,7,2,6,9 %N A329212 Decimal expansion of the fundamental frequency of the note F4 in hertz. %C A329212 In 12-tone equal temperament, when A4 (the fifth A on the Piano keyboard) is tuned to 440 Hz, the frequency of the note F4 (4 semitones below A4) is 440*2^(-4/12) Hz = 349.2 Hz. %H A329212 Wikipedia, <a href="https://en.wikipedia.org/wiki/Piano_key_frequencies">Piano key frequencies</a> %H A329212 <a href="/index/Mu#music">Index entries for sequences based on music</a> %H A329212 <a href="/index/Al#algebraic_03">Index entries for algebraic numbers, degree 3</a> %F A329212 Equals 220 * 2^(2/3). %e A329212 Frequencies of notes in an octave (Hz): %e A329212 >-------------------------------------------------- %e A329212 | %e A329212 | C4 261.6255653005... (A329207) %e A329212 | +--------------------------------------- %e A329212 >----------| C#4/Db4 277.1826309768... (A329208) %e A329212 | +--------------------------------------- %e A329212 | D4 293.6647679174... (A329209) %e A329212 | +--------------------------------------- %e A329212 >----------| D#4/Eb4 311.1269837220... (A329210) %e A329212 | +--------------------------------------- %e A329212 | E4 329.6275569128... (A329211) %e A329212 | %e A329212 >-------------------------------------------------- %e A329212 | %e A329212 | F4 349.2282314330... (this seq) %e A329212 | +--------------------------------------- %e A329212 >----------| F#4/Gb4 369.9944227116... (A329213) %e A329212 | +--------------------------------------- %e A329212 | G4 391.9954359817... (A329214) %e A329212 | +--------------------------------------- %e A329212 >----------| G#4/Ab4 415.3046975799... (A329215) %e A329212 | +--------------------------------------- %e A329212 | A4 440.0000000000 %e A329212 | +--------------------------------------- %e A329212 >----------| A#4/Bb4 466.1637615180... (A329217) %e A329212 | +--------------------------------------- %e A329212 | B4 493.8833012561... (A329218) %e A329212 | %e A329212 >-------------------------------------------------- %e A329212 [New layout from _Jon E. Schoenfield_, Nov 08 2019] %t A329212 RealDigits[220 Surd[4,3],10,120][[1]] (* _Harvey P. Dale_, Jul 31 2021 *) %o A329212 (PARI) default(realprecision, 100); 440 * 2^(-4/12) %Y A329212 See the Example section above for the fundamental frequency of some other notes. %K A329212 nonn,easy,cons %O A329212 3,1 %A A329212 _Jianing Song_, Nov 08 2019