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Revision History for A005371 (Underlined text is an addition; strikethrough text is a deletion.)

Showing entries 1-10 | older changes
A005371 a(n) = L(L(n)), where L(n) are Lucas numbers A000032.
(history; published version)
#59 by Michel Marcus at Mon Jul 03 05:14:08 EDT 2023
STATUS

reviewed

approved

#58 by Joerg Arndt at Mon Jul 03 02:57:30 EDT 2023
STATUS

proposed

reviewed

#57 by Joerg Arndt at Mon Jul 03 02:57:22 EDT 2023
STATUS

editing

proposed

#56 by Joerg Arndt at Mon Jul 03 02:57:19 EDT 2023
LINKS

Andrea Pinos, <a href="/A005371/a005371_3.txt">Approximate values of large terms</a>

#55 by Joerg Arndt at Mon Jul 03 02:57:06 EDT 2023
FORMULA

From Andrea Pinos, May 03 2023: (Start)

a(n) = a(n-1)*a(n-2) + a(n-3)*(-1)^((n-1) mod 3).

a(n) = phi^L(n) - (-1)^((n+1) mod 3) / phi^L(n).

for n==0 (mod 6): a(n) = 2*cosh(log(phi)*2*cosh(n*log(phi)));

for n==1 or n==5 (mod 6): a(n) = 2*sinh(log(phi)*2*sinh(n*log(phi)));

for n==2 or n==4 (mod 6): a(n) = 2*sinh(log(phi)*2*cosh(n*log(phi)));

for n==3 (mod 6): a(n) = 2*cosh(log(phi)*2*sinh(n*log(phi))). (End)

STATUS

proposed

editing

#54 by Michel Marcus at Sat May 13 06:23:12 EDT 2023
STATUS

editing

proposed

Discussion
Tue May 16 09:04
Kevin Ryde: That convergence, when it does converge, is presumably to one of the solutions to Lucas(x) = x (the continuous version of the Lucas function).  I don't find a sequence for that.
09:08
Kevin Ryde: I still think all the sinh and cosh don't match the problem particularly well.
10:32
Andrea Pinos: Ok, the convergence isn't so important for the sequence. But the expressions with hyperbolic functions are a method more fast to do this calculus , similar but not equal to Binet's formula
#53 by Michel Marcus at Sat May 13 06:23:06 EDT 2023
LINKS

Andrea Pinos, <a href="/A005371/a005371_3.txt">approximateApproximate values of large terms</a>

STATUS

proposed

editing

#52 by Andrea Pinos at Sat May 13 05:32:38 EDT 2023
STATUS

editing

proposed

#51 by Andrea Pinos at Sat May 13 05:23:07 EDT 2023
LINKS

Andrea Pinos, <a href="/A005371/a005371_23.txt">forecastapproximate values of large terms</a>

STATUS

proposed

editing

Discussion
Sat May 13 05:32
Andrea Pinos: Ok, I've specified all terms. There is also an interesting thing: with an iteration x->L(x) the function converges to fixed point 0.9762305652308763 for some intervals (for instance 0.68077870383681 < x < 1 ). I've sought something about this. Could be interesting?
#50 by Andrea Pinos at Fri May 12 06:41:01 EDT 2023
STATUS

editing

proposed

Discussion
Fri May 12 20:53
Kevin Ryde: I'm a bit doubtful about the merit of the sinh and cosh forms.  They're presented in A000032 and not sure that expanding them out adds much.
20:59
Kevin Ryde: The word "forecast" is not right.  What's presented is initial decimal digits of large terms (yes?).  Maybe "approximate values of large terms", and a note in the file that the decimals are truncated at those shown.

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Last modified August 29 06:09 EDT 2024. Contains 375510 sequences. (Running on oeis4.)