[seqfan] Re: Are these interesting?

Jonathan Post jvospost3 at gmail.com
Tue Jul 6 08:27:07 CEST 2010


I think so.

On Mon, Jul 5, 2010 at 10:49 PM, Andrew Weimholt
<andrew.weimholt at gmail.com> wrote:
> 1. earliest sequence such that xy | a(x+y)
>
> 1, 1, 2, 12, 12, 360, 60, 1680, 2520, 25200, 2520, 332640, 27720,
> 5045040, 5405400, 2882880,
> 720720, 220540320, 12252240, 4655851200, 4888643760, 5121436320,
> 232792560, 128501493120,
> 26771144400, 696049754400, 240940299600, 2248776129600, 80313433200,
> 69872686884000, 2329089562800, 1155228423148800,
> 4765317245488800, 4909720798382400, 5054124351276000,
> 5198527904169600, 144403552893600, 203031395368401600,
>
> 2. earliest sequence such that (x+y) | a(xy)
>
> 2, 3, 4, 20, 6, 35, 8, 18, 30, 77, 12, 728, 14, 45, 16, 680,
> 18, 1881, 20, 252, 110, 299, 24, 3850, 130, 135, 84, 5104, 30, 75361, 32, 396,
> 238, 665, 36, 28860, 38, 273, 80, 82082, 42, 218569, 44, 360, 2898,
> 1175, 48, 193648,
> 350, 2295, 260, 25228, 54, 33495, 112, 1710, 638, 1829, 60, 14501408,
> 62, 693, 192, 17680,
> 198, 199325, 68, 5796, 910, 848521, 72, 14005926, 74, 975, 2660,
> 70840, 234, 1784689, 80, 4536,
>
> 3. earliest sequence such that xy | a(x+y) and (x+y) | a(xy)
>
> 2, 3, 4, 60, 12, 2520, 120, 5040, 2520, 277200, 2520, 4324320, 27720,
> 5045040, 10810800, 49008960,
> 720720, 4190266080, 12252240, 4655851200, 4888643760, 117793035360,
> 232792560, 642507465600,
> 26771144400, 2088149263200, 240940299600, 65214507758400, 80313433200,
> 2166053293404000,
> 4658179125600, 1155228423148800, 4765317245488800, 4909720798382400,
> 5054124351276000,
>
> Andrew
>
>
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