A323615 a(0) = 1; for n > 0, a(n) = floor(a(n-1)/n) if positive and not already in the sequence, otherwise a(n) = a(n-1)*n.

1, 1, 2, 6, 24, 4, 24, 3, 24, 216, 21, 231, 19, 247, 17, 255, 15, 255, 14, 266, 13, 273, 12, 276, 11, 275, 10, 270, 9, 261, 8, 248, 7, 231, 7854, 224, 8064, 217, 5, 195, 7800, 190, 7980, 185, 8140, 180, 8280, 176, 8448, 172, 8600, 168, 8736, 164

Offset: 0

Author

Jan Koornstra, Jan 20 2019

Keywords

• nonn
• easy
• look

Comments

Variation on A008336 using floor division and A076039 not allowing for values already in the sequence.

Examples

			a(5) = 4, since floor(24/5) = 4, which is positive and not already in the sequence.
a(6) = 24, since floor(4/6) = 0, hence not positive.
		

Links

• Jan Koornstra, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A008336, A076039.

Programs

Mathematica

Nest[Append[#1, If[And[#3 > 0, FreeQ[#1, #3]], #3, #2 #1[[-1]] ]] & @@ {#1, #2, Floor[#1[[-1]]/#2]} & @@ {#, Length@ #} &, {1}, 53] (* Michael De Vlieger, Jan 23 2019 *)

Python

def a323615(n):
  seq = []
  for i in range(n + 1):
    if i == 0: x = 1
    else:
      x = seq[i - 1] // i
      if x in seq or x == 0: x = seq[i - 1] * i
    seq.append(x)
  return seq
print(a323615(100))