This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A187017 Array where the n-th row is the expansion of (1+2*x+...+n*x^(n-1)) * (n+(n-1)*x+...+x^(n-1)). 0
 1, 2, 5, 2, 3, 8, 14, 8, 3, 4, 11, 20, 30, 20, 11, 4, 5, 14, 26, 40, 55, 40, 26, 14, 5, 6, 17, 32, 50, 70, 91, 70, 50, 32, 17, 6, 7, 20, 38, 60, 85, 112, 140, 112, 85, 60, 38, 20, 7, 8, 23, 44, 70, 100, 133, 168, 204, 168, 133, 100, 70, 44, 23, 8, 9, 26, 50, 80, 115, 154, 196, 240, 285, 240, 196, 154, 115, 80, 50, 26, 9 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS EXAMPLE The table starts: 1 2 5 2 3 8 14 8 3 4 11 20 30 20 11 4 PROG (PARI) al(n)=Vec(sum(k=1, n, k*x^(k-1))*sum(k=1, n, k*x^(n-k))) CROSSREFS Cf. A005408(row lengths), A000537(row sums), A115262(a rearrangement), A000330(central diagonal). Sequence in context: A078372 A154751 A197545 * A083381 A197180 A129396 Adjacent sequences:  A187010 A187015 A187016 * A187018 A187019 A187020 KEYWORD nonn,tabf,easy AUTHOR Franklin T. Adams-Watters, Mar 02 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .