A096357 Lcm[{ad(n)}], i.e. the least common multiple of the anti-divisors of n.

2, 3, 6, 4, 30, 15, 6, 84, 42, 40, 90, 36, 30, 33, 2310, 420, 78, 312, 42, 180, 90, 112, 3570, 204, 990, 25080, 114, 60, 126, 4095, 4290, 276, 4830, 24, 150, 23100, 6006, 432, 54, 7140, 14790, 696, 8190, 33852, 17670, 3040, 1386, 1980, 102, 840, 210, 36, 12210

Offset

3,1

Comments

See A066272 for definition of anti-divisor. Offset is 3 because 1 and 2 have no anti-divisors.

Links

Paolo P. Lava, Table of n, a(n) for n = 3..10000

Example

The anti-divisors of 7 are 2,3 and 5, so a(7)=30.
The anti-divisors of 9 are 2 and 6, so a(9)=6.

Mathematica

a096357[n_] := Module[{ad},
ad := Cases[Range[2, n - 1], _?(Abs[Mod[n, #] - #/2] < 1 &)];
If[Length[ad] == 0, 0, LCM @@ ad]] (* Michael De Vlieger, Aug 09 2014*)

Prog

(Python)
from sympy import lcm
A096357 = [lcm([d for d in range(2, n, 2) if n%d and not 2*n%d]+[d for d in range(3, n, 2) if n%d and 2*n%d in [d-1, 1]]) for n in range(3, 10**5)] # Chai Wah Wu, Aug 09 2014

Crossrefs

Cf. A066272.

Sequence in context: A137524 A282507 A156055 * A091507 A098282 A034855

Adjacent sequences: A096354 A096355 A096356 * A096358 A096359 A096360

Keyword

nonn

Author

Jon Perry, Jun 30 2004

Extensions

Offset changed by N. J. A. Sloane, Aug 22 2014

Status

approved