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 A329208 #14 Jun 18 2024 11:08:35 %S A329208 2,7,7,1,8,2,6,3,0,9,7,6,8,7,2,0,9,6,2,4,8,7,8,6,3,3,3,6,0,1,2,1,0,2, %T A329208 3,7,1,2,5,4,5,5,3,2,2,2,3,4,3,3,1,7,5,5,6,1,8,0,3,4,5,2,4,6,7,4,1,6, %U A329208 5,9,2,8,8,3,3,0,7,1,0,8,6,4,2,0,4,6,7,2,4,3,7 %N A329208 Decimal expansion of the fundamental frequency of the note C#4/Db4 in hertz. %C A329208 In 12-tone equal temperament, when A4 (the fifth A on the Piano keyboard) is tuned to 440 Hz, the frequency of the note C#4/Db4 (8 semitones below A4) is 440*2^(-8/12) Hz = 277.2 Hz. %H A329208 Wikipedia, <a href="https://en.wikipedia.org/wiki/Piano_key_frequencies">Piano key frequencies</a> %H A329208 <a href="/index/Mu#music">Index entries for sequences based on music</a> %H A329208 <a href="/index/Al#algebraic_12">Index entries for algebraic numbers, degree 12</a> %F A329208 Equals 220 * 2^(1/3). %e A329208 Frequencies of notes in an octave (Hz): %e A329208 >-------------------------------------------------- %e A329208 | %e A329208 | C4 261.6255653005... (A329207) %e A329208 | +--------------------------------------- %e A329208 >----------| C#4/Db4 277.1826309768... (this seq) %e A329208 | +--------------------------------------- %e A329208 | D4 293.6647679174... (A329209) %e A329208 | +--------------------------------------- %e A329208 >----------| D#4/Eb4 311.1269837220... (A329210) %e A329208 | +--------------------------------------- %e A329208 | E4 329.6275569128... (A329211) %e A329208 | %e A329208 >-------------------------------------------------- %e A329208 | %e A329208 | F4 349.2282314330... (A329212) %e A329208 | +--------------------------------------- %e A329208 >----------| F#4/Gb4 369.9944227116... (A329213) %e A329208 | +--------------------------------------- %e A329208 | G4 391.9954359817... (A329214) %e A329208 | +--------------------------------------- %e A329208 >----------| G#4/Ab4 415.3046975799... (A329215) %e A329208 | +--------------------------------------- %e A329208 | A4 440.0000000000 %e A329208 | +--------------------------------------- %e A329208 >----------| A#4/Bb4 466.1637615180... (A329217) %e A329208 | +--------------------------------------- %e A329208 | B4 493.8833012561... (A329218) %e A329208 | %e A329208 >-------------------------------------------------- %e A329208 [New layout from _Jon E. Schoenfield_, Nov 08 2019] %t A329208 First[RealDigits[220*2^(1/3), 10, 100]] (* _Paolo Xausa_, Jun 18 2024 *) %o A329208 (PARI) default(realprecision, 100); 440 * 2^(-8/12) %Y A329208 See the Example section above for the fundamental frequency of some other notes. %K A329208 nonn,easy,cons %O A329208 3,1 %A A329208 _Jianing Song_, Nov 08 2019