cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A381644 a(n) is the number of positive integer solutions of n*x*y*z*v*w = (x + n) * (y + n) * (z + n) * (v + n) * (w + n), x <= y <= z <= v <= w.

Original entry on oeis.org

0, 21313, 35472, 28901, 36366, 35534, 33048, 55548, 30891, 60741, 76106, 161909, 88494, 114437, 220621, 76856, 56832, 195942, 33510, 212618, 222606, 154046, 21700, 324700, 107022, 94149, 109693, 244884, 35992, 592482, 39051, 134282, 213723, 104829, 363935, 355519, 70334, 110560, 158300, 485946, 46982, 650655
Offset: 1

Views

Author

Zhining Yang, Mar 03 2025

Keywords

Examples

			For n=4, a(4) = 28901 because 4*x*y*z*v*w = (x + 4)*(y + 4)*(z + 4)*(v + 4)*(w + 4), 0 < x <= y <= z <= v <= w has 28901 positive integer solutions: {{2,13,205,42637,1818041676},{2,13,205,42638,909042156},{2,13,205,42639,606042316},{2,13,205,42640,454542396}, ..., {10, 10, 12, 14, 21}, {10, 11, 12, 14, 18}, {10, 12, 12, 14, 16}}.
		

Crossrefs

Programs

  • Mathematica
    Table[Length@Solve[n*x*y*z*v*w == (x + n)  (y + n)  (z + n) (v + n) (w + n) &&
        0 < x <= y <= z <= v <= w, {x, y, z, v, w}, Integers], {n, 8}]