login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A171762 a(n) = Sum_{k=n^2+1..(n+1)^2-1} tau(k). 1

%I #8 Jan 13 2019 03:11:01

%S 4,12,22,34,44,58,72,88,100,120,126,148,164,182,196,220,228,254,264,

%T 284,304,328,338,358,382,400,420,444,442,478,494,518,544,564,562,602,

%U 622,648,652,690,684,730,740,768,790,812,828,858,870,898,920,946,958,990

%N a(n) = Sum_{k=n^2+1..(n+1)^2-1} tau(k).

%F a(n) = A168011(n) - A168011(n-1) - A048691(n). - _R. J. Mathar_, Jan 25 2010

%p A168011 := proc(n) add( numtheory[tau](k),k=1..n^2+2*n) ; end proc: A048691 := proc(n) numtheory[tau](n^2) ; end proc: A171762 := proc(n) A168011(n)-A168011(n-1)-A048691(n) ; end proc: seq(A171762(n),n=1..80) ; # _R. J. Mathar_, Jan 25 2010

%t Array[n \[Function] Sum[DivisorSigma[0, k], {k, n^2 + 1, (n + 1)^2 - 1}], 200] (* J. Mulder (jasper.mulder(AT)planet.nl), Jan 28 2010 *)

%Y Cf. A000005, A048691, A168011.

%K nonn,easy

%O 1,1

%A _Giovanni Teofilatto_, Dec 18 2009

%E Definition corrected by _Giovanni Teofilatto_, Dec 19 2009

%E More terms from _R. J. Mathar_ and J. Mulder (jasper.mulder(AT)planet.nl), Jan 25 2010

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 11 23:45 EDT 2024. Contains 375082 sequences. (Running on oeis4.)