[A000179]

[Christian G. Bower]

"David Wilson" <davidwwilson at attbi.com> wrote:
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> In the OEIS, A000179 starts out 1, 1, 0, 1, 2, 13, 80, ...
> 
> In the Mathworld article "Married Couples Problem", A000179 starts out -1,
1, 0, 2, 13, 80, ...
> 
> Which is correct?
> 

Reading the description in the EIS, I would think a_4 = 1, the only
qualifying permutation being 2301.

a_5 should be 2 with 23401 and 34012

before a_4 there cannot be any. From the Mathworld description, it looks
like terms before a_4 may have been assigned to make the formulas or
recurrences work. I'm having a hard time getting reasonable values out
of any of the formulas. (Maybe I'm making elementary errors.)

In any case, it appears the EIS starting index should be 1, not 0. After
the 0 at a_3, it should be 1, 2, ... as in the EIS, not 2, ... as in
Mathworld and if anybody can figure out whether the terms before the
zero are better as 1,1 or -1,1 or 0,0 or something else, please speak up.

Christian