VOOZH about

URL: https://oeis.org/A092971

⇱ A092971 - OEIS

login
A092971
Row 6 of array in A288580.
7
1, 1, 2, -9, -8, -5, -36, -35, -64, 729, 640, 385, 5184, 5005, 8960, -164025, -143360, -85085, -1679616, -1616615, -2867200, 72335025, 63078400, 37182145, 967458816, 929553625, 1640038400, -52732233225, -45921075200, -26957055125, -870712934400, -835668708875, -1469474406400, 57425401982025
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, k) = !n!_k = Prod_{i=0, 1, 2, .., floor(2n/k)}_{0<|n-i*k|<=n} (n-i*k) = n(n-k)(n-2k)(n-3k)... . k=6.
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(6); # N. J. A. Sloane, Jul 03 2017
PROG
(PARI) a(n, k)=prod(j=0, (2*n)\k, if(n-k*j==0, 1, n-k*j))
KEYWORD
sign
AUTHOR
EXTENSIONS
Entry revised by N. J. A. Sloane, Jul 03 2017
STATUS
approved