A232983 The Gauss factorial n_7!.

1, 1, 2, 6, 24, 120, 720, 720, 5760, 51840, 518400, 5702400, 68428800, 889574400, 889574400, 13343616000, 213497856000, 3629463552000, 65330343936000, 1241276534784000, 24825530695680000, 24825530695680000, 546161675304960000, 12561718532014080000, 301481244768337920000, 7537031119208448000000

Offset

0,3

Comments

The Gauss factorial n_k! is defined to be Product_{1<=j<=n, gcd(j,k)=1} j.

Links

Table of n, a(n) for n=0..25.

J. B. Cosgrave and K. Dilcher, An introduction to Gauss factorials, Amer. Math. Monthly, 118 (2011), 810-828.

J. B. Cosgrave and K. Dilcher, The Gauss-Wilson theorem for quarter-intervals, Acta Mathematica Hungarica, Sept. 2013.

Maple

Gf:=proc(N, n) local j, k; k:=1;
for j from 1 to N do if gcd(j, n)=1 then k:=j*k; fi; od; k; end;
f:=n->[seq(Gf(N, n), N=0..40)];
f(7);

Prog

(Magma) k:=7; [IsZero(n) select 1 else &*[j: j in [1..n] | IsOne(GCD(j, k))]: n in [0..30]]; // Bruno Berselli, Dec 10 2013

Crossrefs

The Gauss factorials n_1!, n_2!, n_3!, n_5!, n_6!, n_7!, n_10!, n_11! are A000142, A055634, A232980-A232985 respectively.

Sequence in context: A033644 A212309 A319546 * A319207 A380271 A263749

Adjacent sequences: A232980 A232981 A232982 * A232984 A232985 A232986

Keyword

nonn,changed

Author

N. J. A. Sloane, Dec 08 2013

Status

approved