login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A230293 a(n) = Sum_{i=1..n} d(8*i+1) - Sum_{i=1..n} d(4*i+1), where d(n) = A000005(n). 4
1, 0, 1, 3, 1, 1, 3, 3, 3, 6, 2, 1, 7, 5, 6, 6, 4, 6, 8, 7, 6, 8, 8, 8, 10, 6, 8, 15, 11, 10, 10, 8, 8, 14, 12, 11, 17, 15, 15, 15, 11, 10, 16, 14, 15, 17, 13, 19, 21, 19, 17, 17, 19, 17, 22, 15, 15, 21, 21, 23, 21, 21, 21, 27, 23, 22, 24, 20, 22, 28, 22, 21, 31, 25, 23, 27, 25, 28, 30, 28, 26, 28, 30, 30, 30, 26, 28 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..87.

Jorge Luis Cimadevilla Villacorta, Certain inequalities associated with the divisor function, Amer. Math. Monthly, 120 (2013), 832-837. (Shows that a(n) >= 0.)

FORMULA

a(n) = A230476(n) - A230294(n). - Jonathan Sondow, Oct 20 2013

MAPLE

See A230290.

PROG

(PARI) vector(100, n, sum(i=1, n, numdiv(8*i+1)) - sum(i=1, n, numdiv(4*i+1))) \\ Michel Marcus, Oct 09 2014

CROSSREFS

Cf. A000005, A230290-A230296, A230476.

Sequence in context: A035666 A060592 A080426 * A133116 A059959 A192812

Adjacent sequences:  A230290 A230291 A230292 * A230294 A230295 A230296

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Oct 17 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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 25 19:30 EDT 2020. Contains 334595 sequences. (Running on oeis4.)