A181913 - OEIS

%I #16 Apr 02 2012 23:06:56

%S 3,7,0,2,1,5,4,9,2,8,1,5,3,5,8,8,7,7,0,2,2,2,6,1,2,3,1,2,4,2,6,4,1,3,

%T 6,5,5,9,1,8,6,0,3,4,2,5,9,4,6,7,0,0,8,1,7,5,7,5,0,4,2,7,8,9,9,3,5,4,

%U 6,2,6,6,2,0,1,5,8,4,7,0,9,4,8,9,6,9,1,3,1,9,8,8,4,4,4,9,7,1,2,6

%N The value of r at the bifurcation point of the first period-7 cycle of the logistic map f(x) = r*x*(1 - x).

%C Root of a degree 63*2 = 126 polynomial.

%e 3.702154928...

%t RealDigits[1 + Sqrt[1 + T] /.  NSolve[97862157334118736160267353892330031361 - 24275883989858911295570196314376441888 T + 11949756847721247033090755550100031472 T^2 - 7305759525507048491687489710934851842 T^3 + 4979912078948645588349153608449721856 T^4 - 3626559126667087845228068253830569728 T^5 + 2762422187660818660072532819743957008 T^6 - 1880399068065596812679449750312116489 T^7 + 1211937495049324668386707923551814144 T^8 - 759866924055411176816609501610145824 T^9 + 466557599052858501899389873590498576 T^10 - 280965824140635821336538113950238208 T^11 + 165486490562715543623266844910996960 T^12 - 95328733468347624721143436596991728 T^13 + 53730737569188242850960902675061540 T^14 - 29631735433275573295736684905520448 T^15 + 15982002519220233506297359288643328 T^16 - 8426732734596962888735943308790072 T^17 + 4341578043750972227945942898034432 T^18 - 2184193663643426076323203313845088 T^19 + 1072045107586559381111681621669072 T^20 - 512897616845631175409335289338708 T^21 + 239007878643078614755697662563584 T^22 - 108415793383957757795350567428064 T^23 + 47846270482094728117141329426032 T^24 - 20533661180243125068599265318144 T^25 + 8564906198781819799124804441280 T^26 - 3470264291680473250164651552944 T^27 + 1364870535759255877272510765950 T^28 - 520676891296255096870756895040 T^29 + 192488968788190123648373004064 T^30 - 68893036110679144584159460492 T^31 + 23845858487001866959614915840 T^32 - 7973063091544280406837942464 T^33 + 2572118763623299179804574640 T^34 - 799578831968317708137874814 T^35 + 239196982314145129630174464 T^36 - 68763448836715397230901728 T^37 + 18967378806716848507574128 T^38 - 5011787964028065103857408 T^39 + 1266306625250424841996640 T^40 - 305348843999288091901136 T^41 + 70117811645069434371412 T^42 - 15296768944400171831616 T^43 + 3162019501419003256064 T^44 - 617525327585232743224 T^45 + 113570706028361676288 T^46 - 19599347048769496032 T^47 + 3161153679144274672 T^48 - 474387152691155748 T^49 + 65902567592614400 T^50 - 8426269030832672 T^51 + 984947439372048 T^52 - 104425099694592 T^53 + 9947578647040 T^54 - 841756889488 T^55 + 62385936393 T^56 - 3978343968 T^57 + 213336304 T^58 - 9328642 T^59 + 318464 T^60 - 7936 T^61 + 128 T^62 - T^63 == 0, T, Reals, WorkingPrecision -> 200][[1]][[1]]][[1]]

%Y Cf. A086178, A086179, A086180, A086181, A091517, A118452, A118453, A118746, A181906, A181907, A181909, A181910, A181911, A181912, A181915, A181916, A181917, A181918, A181919.

%K nonn,cons

%O 1,1

%A _Cheng Zhang_, Apr 01 2012