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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A088840 Denominator of sigma(4n)/sigma(n). 4
1, 1, 1, 7, 1, 1, 1, 5, 1, 1, 1, 7, 1, 1, 1, 31, 1, 1, 1, 7, 1, 1, 1, 5, 1, 1, 1, 7, 1, 1, 1, 21, 1, 1, 1, 7, 1, 1, 1, 5, 1, 1, 1, 7, 1, 1, 1, 31, 1, 1, 1, 7, 1, 1, 1, 5, 1, 1, 1, 7, 1, 1, 1, 127, 1, 1, 1, 7, 1, 1, 1, 5, 1, 1, 1, 7, 1, 1, 1, 31, 1, 1, 1, 7, 1, 1, 1, 5, 1, 1, 1, 7, 1, 1, 1, 21, 1, 1, 1, 7, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for sequences related to sigma(n)

MATHEMATICA

Table[Numerator[DivisorSigma[1, 4*n]/DivisorSigma[1, n]], {n, 1, 128}]

PROG

(PARI) A088840(n) = denominator(sigma(4*n)/sigma(n)); \\ Antti Karttunen, Nov 18 2017

CROSSREFS

See A088839 for numerator.

Cf. A088837, A088838, A088841, A038712, A080278, A000203.

Sequence in context: A174544 A168423 A072101 * A271498 A317940 A318674

Adjacent sequences:  A088837 A088838 A088839 * A088841 A088842 A088843

KEYWORD

easy,nonn,mult,frac

AUTHOR

Labos Elemer, Nov 04 2003

EXTENSIONS

Typo in definition corrected by Antti Karttunen, Nov 18 2017

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 July 23 11:44 EDT 2019. Contains 325254 sequences. (Running on oeis4.)