nice stuff, as Xmass present, I offer you 3.92065141231007653868232570898716939515935444313 which correctly Plouffe-inverts to Sum[(5/2*n^3 - 10*n^2 + 27/2*n - 4)/Binomial[2*n, n], {n, 1, Infinity}] aha, this equals Hypergeometric2F1[3, 4, 5/2, 1/4] which again equals 8/243*(81 + 7*Sqrt[3]*Pi) see? start anywhere, and you get Pi staring back at you. hmmm, can this be coincidence? ;-)) Wouter. -----Original Message----- From: Simon Plouffe [mailto:simon.plouffe@sympatico.ca] Sent: donderdag 19 december 2002 8:34 To: math-fun@mailman.xmission.com Subject: [math-fun] Inverse Symbolic Calculator and plouffe's inverter. hello, I agree the <reveng> engine is useless because of that java program which does not work for most people and platforms. (I did not programmed that junk!, I made the ISC only). The Inverse Symbolic Calculator still works there at the cecm, they did not unplugged my project there yet. http://www.cecm.sfu.ca/projects/ISC/ it uses the online (but limited) set of tests with 46 million constants. For lookups only I made the Inverter at http://pi.lacim.uqam.ca/eng/ and if you want a real test with 200 milllion constants + a real inverter which uses GFUN, Pari-GP with LLL you still can ask me to run a test on any number mail you number of any size to numbers@math.uqam.ca and I will run the tests on it. Of course : because of the exponential growth of CPU needed for solving anycase that has approx. 50 digits or more this last step is done interactively by me manually. I still could not find a way to automate that last step. Ah yes, the OEIS is embedded into the Inverter, I made a conversion of the integer sequences into real numbers using 18 different algorithms in 1999. I counted about 2 million entries that are made with the OEIS entries. Just in case that an unknown combination of integer sequence would lead to any interesting real number, and vice-versa. Simon Plouffe _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun =============================== This email is confidential and intended solely for the use of the individual to whom it is addressed. If you are not the intended recipient, be advised that you have received this email in error and that any use, dissemination, forwarding, printing, or copying of this email is strictly prohibited. You are explicitly requested to notify the sender of this email that the intended recipient was not reached.