A092972 Row 7 of array in A288580.

1, 1, 2, 3, -12, -10, -6, -49, -48, -90, -120, 1320, 1080, 624, 9604, 9360, 17280, 22440, -403920, -328320, -187200, -4235364, -4118400, -7551360, -9694080, 242352000, 196335360, 111196800, 3320525376, 3224707200, 5890060800, 7512912000, -240413184000, -194372006400, -109640044800

Offset

0,3

References

F. Smarandache, Back and Forth Factorials, Arizona State Univ., Special Collections, 1972.

Links

Table of n, a(n) for n=0..34.

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=7.

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(7); # 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))

Crossrefs

Cf. A288580, A092396, A092397, A092398, A092399, A092971, A092973, A092974.

Sequence in context: A104038 A112979 A225723 * A334914 A261576 A081526

Adjacent sequences: A092969 A092970 A092971 * A092973 A092974 A092975

Keyword

sign

Author

Paul D. Hanna, M.L. Perez and Amarnath Murthy, Mar 27 2004

Extensions

Entry revised by N. J. A. Sloane, Jul 03 2017

Status

approved