OFFSET
0,2
COMMENTS
Number of tilings of a <5,n,5> hexagon.
REFERENCES
O. D. Anderson, Find the next sequence, J. Rec. Math., 8 (No. 4, 1975-1976), 241.
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000
O. D. Anderson, Find the next sequence, J. Rec. Math., 8 (No. 4, 1975-1976), 241. [Annotated scanned copy]
FORMULA
a(n) = C(n+5,n+4)*C(n+6,n+3)*C(n+7,n+2)*C(n+8,n+1)*C(n+9,n)/(140*5!). - Zerinvary Lajos, May 29 2007
MAPLE
seq(binomial(n+5, n+4)*binomial(n+6, n+3)*binomial(n+7, n+2)*binomial(n+8, n+1)*binomial(n+9, n)/(140*5!), n=0..17); # Zerinvary Lajos, May 29 2007
MATHEMATICA
Table[Product[Times@@(i+Range[5, 9])/Times@@(i+Range[0, 4]), {i, n}], {n, 0, 20}] (* Harvey P. Dale, Jan 30 2015 *)
PROG
(PARI) a(n) = prod(k=1, 5, binomial(n+k+4, n-k+5))/(140*5!); \\ Seiichi Manyama, Apr 02 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Definition corrected by Daniel Soll (soll(AT)mathematik.uni-marburg.de), Aug 31 2004
STATUS
approved