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 A329210 #14 Jun 18 2024 11:08:31 %S A329210 3,1,1,1,2,6,9,8,3,7,2,2,0,8,0,9,1,0,7,3,6,3,7,1,5,1,9,3,2,6,1,3,3,5, %T A329210 7,7,2,8,5,3,2,7,8,1,2,5,8,2,9,2,8,5,7,6,0,9,8,8,6,9,5,4,2,3,5,7,9,6, %U A329210 1,1,4,5,2,6,1,6,6,3,5,4,8,5,4,7,0,8,5,2,5,7,5 %N A329210 Decimal expansion of the fundamental frequency of the note D#4/Eb4 in hertz. %C A329210 In 12-tone equal temperament, when A4 (the fifth A on the Piano keyboard) is tuned to 440 Hz, the frequency of the note D#4/Eb4 (6 semitones below A4) is 440*2^(-6/12) Hz = 311.1 Hz. %H A329210 Wikipedia, <a href="https://en.wikipedia.org/wiki/Piano_key_frequencies">Piano key frequencies</a> %H A329210 <a href="/index/Mu#music">Index entries for sequences based on music</a> %H A329210 <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a> %F A329210 Equals 220 * sqrt(2). %e A329210 Frequencies of notes in an octave (Hz): %e A329210 >-------------------------------------------------- %e A329210 | %e A329210 | C4 261.6255653005... (A329207) %e A329210 | +--------------------------------------- %e A329210 >----------| C#4/Db4 277.1826309768... (A329208) %e A329210 | +--------------------------------------- %e A329210 | D4 293.6647679174... (A329209) %e A329210 | +--------------------------------------- %e A329210 >----------| D#4/Eb4 311.1269837220... (this seq) %e A329210 | +--------------------------------------- %e A329210 | E4 329.6275569128... (A329211) %e A329210 | %e A329210 >-------------------------------------------------- %e A329210 | %e A329210 | F4 349.2282314330... (A329212) %e A329210 | +--------------------------------------- %e A329210 >----------| F#4/Gb4 369.9944227116... (A329213) %e A329210 | +--------------------------------------- %e A329210 | G4 391.9954359817... (A329214) %e A329210 | +--------------------------------------- %e A329210 >----------| G#4/Ab4 415.3046975799... (A329215) %e A329210 | +--------------------------------------- %e A329210 | A4 440.0000000000 %e A329210 | +--------------------------------------- %e A329210 >----------| A#4/Bb4 466.1637615180... (A329217) %e A329210 | +--------------------------------------- %e A329210 | B4 493.8833012561... (A329218) %e A329210 | %e A329210 >-------------------------------------------------- %e A329210 [New layout from _Jon E. Schoenfield_, Nov 08 2019] %t A329210 First[RealDigits[220*Sqrt[2], 10, 100]] (* _Paolo Xausa_, Jun 18 2024 *) %o A329210 (PARI) default(realprecision, 100); 440 * 2^(-6/12) %Y A329210 See the Example section above for the fundamental frequency of some other notes. %K A329210 nonn,easy,cons %O A329210 3,1 %A A329210 _Jianing Song_, Nov 08 2019