duplicate hunting, pt. 9

[Andrew Plewe]

On 5/2/07, Andrew Plewe <aplewe at sbcglobal.net> wrote:
> A119786 and A120300

Yup, definitely equivalent definitions.  In fact A119786 has two
mathematica codes and the second code there is the same as the code in
A120300.

> A092956 and A126696

The offset differs by 2, and if you substitute n -> n-2 to account for
that offset, then you get the identical formula.

>
> Sequences A076096 and A081968 reference sequences A076099 and A081967
> respectively, which differ from each other by one term:
>
> A076099(28) = 12011154239478262707557453127548617090909593750
> A081967(28) = 11022732501667945875061568782593750
>
> It appears that if the 28th term in A081967 is wrong, then so is sequence
> A081968 which, I believe, is supposed to reference that term (A081968(7)).
> If the 28th terms match, then A076099 and A081967 are duplicates along with
> A076096 and A081968.

I think the two sequences SHOULD be the same but that A076099 is the
one that's wrong here.  I get 11022732501667945875061568782593750 = 2
* 3^5 * 5^6 * 7^6 * 11^6 * 23^6 as the term that goes with
19,20,21,22,23,24.

Looks like both were submitted by the same author, then "corrected"
and extended by different people ...

A076098 looks correct, though, so maybe at some time later A076099 was
corrupted.  (I only checked A076098 up to the term corresponding to
this 28th term above).  It's odd that all the derivative sequences are
extended correctly -- maybe just a typo in A076099 and then all the
rest are straightforward duplicates.

--Joshua Zucker