VOOZH about

URL: https://oeis.org/A092974

⇱ A092974 - OEIS

login
A092974
Row 9 of array in A288580.
7
1, 1, 2, 3, 4, -20, -18, -14, -8, -81, -80, -154, -216, -260, 3640, 3240, 2464, 1360, 26244, 25840, 49280, 68040, 80080, -1841840, -1632960, -1232000, -671840, -19131876, -18811520, -35728000, -48988800, -57097040, 1827105280, 1616630400, 1214752000, 658403200, 24794911296, 24360918400
OFFSET
0,3
REFERENCES
F. Smarandache, Back and Forth Factorials, Arizona State Univ., Special Collections, 1972.
LINKS
J. Dezert, ed., Smarandacheials (1), Mathematics Magazine for Grades 1-12, No. 4, 2004.
J. Dezert, ed., Smarandacheials (2), Mathematics Magazine for Grades 1-12, No. 4, 2004.
FORMULA
a(n) = T(n, k) = !n!_k = Product_{i=0..floor(2n/k)}_{0<|n-i*k|<=n} (n-i*k) = n(n-k)(n-2k)(n-3k)... with k=9.
MAPLE
T:=proc(n, k) local i, p;
p:=1;
for i from 0 to floor(2*n/k) do
if n-k*i <> 0 then p:=p*(n-k*i) fi; od:
p;
end;
r:=k->[seq(T(n, k), n=0..60)]; r(9); # N. J. A. Sloane, Jul 03 2017
PROG
(PARI) T(n, k)=prod(j=0, (2*n)\k, if(n-k*j==0, 1, n-k*j));
a(n) = T(n, 9);
KEYWORD
sign
AUTHOR
Paul D. Hanna, M.L. Perez and Amarnath Murthy, Mar 27 2004
STATUS
approved