This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A084939 Pentagorials: n-th polygorial for k=5. 20

%I

%S 1,1,5,60,1320,46200,2356200,164934000,15173928000,1775349576000,

%T 257425688520000,45306921179520000,9514453447699200000,

%U 2350070001581702400000,674470090453948588800000,222575129849803034304000000

%N Pentagorials: n-th polygorial for k=5.

%F A084939(n) = Polygorial(n, 5) = A000142(n)/A000079(n)*A008544(n) = n!/2^n*product(3*i+2, i=0..n-1) = n!/2^n*3^n*pochhammer(2/3, n) = n!/2^n*3^n*GAMMA(n+2/3)/GAMMA(2/3)

%p a := n->n!/2^n*mul(3*i+2,i=0..n-1); [seq(a(j),j=0..30)];

%t Table[k! Pochhammer[2/3, k] (3/2)^k, {k, 0, 20}] (* _Jan Mangaldan_, Mar 20 2013 *)

%Y Cf. A006472, A001044, A000680, A084940, A084941, A084942, A084943, A084944, A085356.

%K easy,nonn

%O 0,3

%A Daniel Dockery (peritus(AT)gmail.com) Jun 13 2003

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 .