[seqfan] Re: Like A6919, but starting with 20
Sean A. Irvine
sairvin at gmail.com
Fri Oct 7 20:50:50 CEST 2022
All these kinds of sequences have been hammered a lot by the integer
factorization folk. You can find plenty of results at factordb.com, e.g.:
Tricky start points include 49, 146, 242, 312, ...
On Sat, 8 Oct 2022 at 03:19, Alonso Del Arte <alonso.delarte at gmail.com>
> The 13th term of A6919 is a prime number, thereby reaching a fixed point.
> I've played around with similar sequences with different starting points.
> Most of the ones I've looked at quickly reach a prime. But the one starting
> with 20, if my calculations are correct, goes like this
> 20, 225, 3355, 51161, 114651, 3312739, 17194867, 194122073, 709273797,
> 39713717791, 113610337981, 733914786213, 3333723311815403,
> 131723655857429041, 772688237874641409, 3318308475676071413
> I do believe this one too reaches a prime eventually. Can someone verify
> what I've got so far?
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