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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A106847 a(n) = Sum {k + l*m <= n} (k + l*m), with 0 < k,l,m <= n. 4
 0, 0, 2, 11, 31, 71, 131, 229, 357, 537, 767, 1064, 1412, 1867, 2385, 3000, 3720, 4570, 5506, 6608, 7808, 9194, 10734, 12436, 14260, 16360, 18622, 21079, 23739, 26668, 29758, 33199, 36815, 40742, 44924, 49369, 54085, 59265, 64661, 70355 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS M. F. Hasler, Table of n, a(n) for n = 0..9999 EXAMPLE We have 1+1*1=2<=3, 1+2*1=3, 1+1*2=3, 2+1*1=3, thus a(3)=2+3+3+3=11. MAPLE A106847 := proc(n)     local a, k, l, m ;     a := 0 ;     for k from 1 to n do         for l from 1 to n-k do             m := floor((n-k)/l) ;             if m >=1 then                 m := min(m, n) ;                 a := a+m*k+l*m*(m+1)/2 ;             end if;         end do:     end do:     a ; end proc: # R. J. Mathar, Oct 17 2012 PROG (PARI) A106847(n)=sum(m=1, n-1, sum(k=1, (n-1)\m, (n-m*k)*(n+m*k+1)))/2  \\ - M. F. Hasler, Oct 17 2012 CROSSREFS Cf. A106633, A106634, A106846, A078567 (number of terms). Sequence in context: A085041 A197642 A121346 * A092761 A296733 A087933 Adjacent sequences:  A106844 A106845 A106846 * A106848 A106849 A106850 KEYWORD nonn AUTHOR Ralf Stephan, May 06 2005 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 July 31 18:30 EDT 2021. Contains 346376 sequences. (Running on oeis4.)