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A092398 Row 4 of array in A288580. 8
1, 1, -4, -3, -16, -15, 144, 105, 1024, 945, -14400, -10395, -147456, -135135, 2822400, 2027025, 37748736, 34459425, -914457600, -654729075, -15099494400, -13749310575, 442597478400, 316234143225, 8697308774400, 7905853580625, -299195895398400, -213458046676875, -6818690079129600, -6190283353629375 (list; graph; refs; listen; history; text; internal format)
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..29.

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) = !n!_4 = Prod_{i=0, 1, 2, ... .}_{0<|n-4i|<=n}(n-4i) = n(n-4)(n-8)....

EXAMPLE

!9!_4 = 9(9-4)(9-8)(9-12)(9-16) = 9(5)(1)(-3)(-7) = 945.

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(4); # N. J. A. Sloane, Jul 03 2017

CROSSREFS

Cf. A288580.

Sequence in context: A278469 A280976 A285646 * A288199 A127675 A058557

Adjacent sequences:  A092395 A092396 A092397 * A092399 A092400 A092401

KEYWORD

sign

AUTHOR

J. Dezert (Jean.Dezert(AT)onera.fr), Mar 21 2004

EXTENSIONS

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

STATUS

approved

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Last modified April 3 14:34 EDT 2020. Contains 333197 sequences. (Running on oeis4.)