This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A129481 a(n) = coefficient of x^n in n!*Product_{k=0..n} [Sum_{j=0..k} x^j/j! ]. 0
 1, 1, 3, 19, 175, 2111, 31321, 550810, 11194177, 258068893, 6653230111, 189653427206, 5922604033567, 201075967613262, 7373834652641003, 290474615891145106, 12232735359488840833, 548429151685677131389 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS EXAMPLE a(2) = [x^2] 2!*(1)*(1+x)*(1+x+x^2/2!) = [x^2] (2 +4*x +3*x^2 +x^3) = 3. a(3) = [x^3] 3!*(1)*(1+x)*(1 + x + x^2/2!)*(1 + x + x^2/2! + x^3/3!) = [x^3] (6 + 18*x + 24*x^2 + 19*x^3 +...) = 19. PROG (PARI) {a(n)=n!*polcoeff(prod(k=0, n, sum(j=0, k, x^j/j!)+x*O(x^n)), n)} CROSSREFS Sequence in context: A143768 A083071 A045531 * A156131 A161630 A121083 Adjacent sequences:  A129478 A129479 A129480 * A129482 A129483 A129484 KEYWORD nonn AUTHOR Paul D. Hanna, Apr 17 2007 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 .