Re superseeker's mysterious report on 3-D billiard sequence --- I fed A180238 to gfun via Maple9 --- and strange to say, gfun replied straight away "FAIL". So as I suspected, it is nonsense; and there appear to be bugs both in the way superseeker is to utilising the gfun package, and its output of the results; while the documentation leaves something to be desired (like, some documentation)! However, the OEIS site has no machinery in evidence for reporting bugs; so it seems I'll just have to leave things there for now ... WFL On 8/19/10, Fred lunnon <fred.lunnon@gmail.com> wrote:
... As suggested by the OEIS instructions, I also fed the first 10, and later all 31, computed values of f_3(n) to superseeker; and received the following replies (fixed spacing) ---
<< Superseeker finds ... 2 3 [-27 + 27 a(n) - 9 a(n) + a(n) , lgdegf]
2 3 4 5 [-243 + 405 a(n) - 270 a(n) + 90 a(n) - 15 a(n) + a(n) , lgdegf]
where "lgdegf" stands for "logarithmic derivative of exponential generating function" The polynomials are simply (a(n) - 3)^3 and (a(n) - 3)^5 respectively.
It's possibly that superseeker has discovered something relatively important here --- unfortunately, I have no idea what that might be, can find no assistance in the documentation, and have failed to put any construction on the phrase which stands up to numerical confirmation.
Can somebody please enlighten me? Fred Lunnon
On 8/21/10, N. J. A. Sloane <njas@research.att.com> wrote:
Yes, I am on the math-fun mailing list!
The lgdegf search does refer to log deriv of a generating function
If you go to the foot of any OEIS page, and click on Superseeker, you will see more about what Superseeker does, including all the source code
It uses the Maple gfun package to search for generating functions. See for example pictor.math.uqam.ca/~plouffe/articles/gfun.pdf
Neil