A373286 a(n) = Product_{k=1..n} (k^2 mod n if k^2 mod n > 0).

1, 1, 1, 1, 16, 48, 64, 16, 784, 233280, 291600, 20736, 167961600, 281014272, 74649600, 1679616, 3229640294400, 2472693350400, 511642685030400, 2751882854400, 4854321355161600, 2085841207296000000, 216982220508758016, 15850845241344, 25975097361564696576

Offset

1,5

Comments

a(n) mod A372651(n) = 0.

Links

Table of n, a(n) for n=1..25.

Mathematica

a[n_]:=Product[Max[Mod[k^2, n], 1], {k, n}]; Array[a, 25] (* Stefano Spezia, May 30 2024 *)

Prog

(Python)
def a(n):
  tmp = 1
  for i in range(1, n+1):
    if (k := pow(i, 2, n)): tmp *= k
  return tmp
print([a(n) for n in range(1, 26)])
(PARI) a(n) = my(x); prod(k=1, n, if ((x=lift(Mod(k, n)^2))>0, x, 1)); \\ Michel Marcus, May 30 2024

Crossrefs

Cf. A165909, A230366, A372651.

Sequence in context: A235548 A223440 A223402 * A260985 A322448 A374588

Adjacent sequences: A373283 A373284 A373285 * A373287 A373288 A373289

Keyword

nonn

Author

Darío Clavijo, May 30 2024

Status

approved