login
This site is supported by donations to The OEIS Foundation.

 

Logo

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!)
A162918 Natural numbers n such that there are s and w satisfying 0 < s < w and 2*s + 5*w = n. 0
12, 17, 19, 22, 24, 26, 27, 29, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Number of equal microtone intervals dividing a musical octave, so that it is (formally) possible to compose one octave (according to the diatonic scale) of two semi-tone-steps and five whole-tone-steps, each being a multiple of the microtone interval.

LINKS

Table of n, a(n) for n=1..69.

Analysis of equal temperament tuning systems (German language)

EXAMPLE

12 = 2*1 + 5*2

17 = 2*1 + 5*3

19 = 2*2 + 5*3

22 = 2*1 + 5*4

...

MATHEMATICA

Union[2*First[#]+5*Last[#]&/@Subsets[Range[20], {2}]] (* Harvey P. Dale, Mar 28 2012 *)

PROG

(Other) Haskell expression:

filter (\n -> [ (s, w) | s<-[1..n], w<-[(s+1)..n], 2*s+5*w == n ] /= []) [1..]

CROSSREFS

Sequence in context: A059390 A179243 A064825 * A105018 A154488 A302359

Adjacent sequences:  A162915 A162916 A162917 * A162919 A162920 A162921

KEYWORD

nonn

AUTHOR

Jan Behrens (jbe-oeis(AT)magnetkern.de), Jul 17 2009

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 13 09:58 EST 2019. Contains 329968 sequences. (Running on oeis4.)