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!)
 A211792 Number of ordered triples (w,x,y) such that x and y are in {1,...,n} and w^3<=x^3+y^3. 3
 1, 7, 22, 51, 97, 164, 258, 382, 541, 741, 982, 1271, 1611, 2008, 2466, 2986, 3577, 4241, 4982, 5807, 6715, 7714, 8808, 10000, 11297, 12701, 14217, 15848, 17600, 19477, 21482, 23620, 25895, 28313, 30879, 33592, 36460, 39487, 42678, 46036 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Row 3 of A211798. LINKS FORMULA Sum{sum{floor((x^3+y^3)^(1/3)), 1<=x<=n, 1<=y<=n}}. EXAMPLE The 7 triples counted by a(2): (1,1,1), (1,1,2), (1,2,1), (1,2,2), (2,1,2), (2,2,1), (2,2,2). MATHEMATICA f[x_, y_, k_] := f[x, y, k] = Floor[(x^k + y^k)^(1/k)] t[k_, n_] := Sum[Sum[f[x, y, k], {x, 1, n}], {y, 1, n}] Table[t[1, n], {n, 1, 45}]  (* 2*A002411 *) Table[t[2, n], {n, 1, 45}]  (* A211791 *) Table[t[3, n], {n, 1, 45}]  (* A211792 *) TableForm[Table[t[k, n], {k, 1, 12},                  {n, 1, 16}]] (* A211798 *) Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]] CROSSREFS Cf. A211798. Sequence in context: A002412 A211652 A211650 * A211635 A211634 A184629 Adjacent sequences:  A211789 A211790 A211791 * A211793 A211794 A211795 KEYWORD nonn AUTHOR Clark Kimberling, Apr 26 2012 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 April 16 00:02 EDT 2021. Contains 343020 sequences. (Running on oeis4.)