This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A214832 Integer part of A440 piano key frequencies, start with A0 = the 1st key. 4
 27, 29, 30, 32, 34, 36, 38, 41, 43, 46, 48, 51, 55, 58, 61, 65, 69, 73, 77, 82, 87, 92, 97, 103, 110, 116, 123, 130, 138, 146, 155, 164, 174, 184, 195, 207, 220, 233, 246, 261, 277, 293, 311, 329, 349, 369, 391, 415, 440, 466, 493, 523, 554, 587, 622, 659, 698, 739, 783, 830, 880, 932, 987, 1046, 1108, 1174, 1244, 1318, 1396, 1479, 1567, 1661, 1760, 1864, 1975, 2093, 2217, 2349, 2489, 2637, 2793, 2959, 3135, 3322, 3520, 3729, 3951, 4186 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A254531(a(k)) = k, k = 1..88. - Reinhard Zumkeller, Feb 04 2015 LINKS BGfL, A Virtual Keyboard Wikipedia, Piano Key Frequencies Wikipedia, Twelfth root of two FORMULA a(n) = floor[2^((n-49)/12)*440] (Hz) for 1 <= n <= 88. EXAMPLE Middle C is 261.626 Hz so a(40) = 261. PROG (JavaScript) for (i=1; i<=88; i++) document.write(Math.floor(Math.pow(2, (i-49)/12)*440)+", "); (PARI) a(n)=floor(440*2^((n-49)/12)); (Haskell) a214832 = floor . (* 440) . (2 **) . (/ 12) . fromIntegral . subtract 49 -- Reinhard Zumkeller, Nov 23 2014 CROSSREFS Cf. A059620, A079731, A131062, A101285, A131071. Cf. A254531, A010774. Sequence in context: A042509 A042510 A157251 * A050876 A051243 A090043 Adjacent sequences:  A214829 A214830 A214831 * A214833 A214834 A214835 KEYWORD nonn,fini,full AUTHOR Jon Perry, Mar 07 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 6 21:45 EST 2019. Contains 329809 sequences. (Running on oeis4.)