[math-fun] Re: Asymptotic for A058797
"Franklin T. Adams-Watters" <franktaw@netscape.net> wrote:
The entry for A058797 states that it is asymptotic to c*n!, with c=.224... I conjecture that c = BesselJ(0,2) = Sum (-1)^k/(k!)^2 = 0.223890779... (A091681).
I found a formula for A007754: a(n,k) = Pi*(BesselJ(n+k+1,2)*BesselY(k,2) - BesselY(n+k+1,2)*BesselJ(k,2)) In particular, for k=0, we get a formula for A058797, a(n) = Pi (BesselJ(n + 1, 2)*BesselY(0, 2) - BesselY(n + 1, 2) BesselJ(0, 2)) Now, BesselJ(n+1,2) ~ 1/(n+1)! and BesselY(n+1,2) ~ -n!/Pi That gives exactly that asymptotics, a(n) ~ BesselJ(0,2)*n! Similarly, the asymptotics for the k-th column of A007754 is a(n,k) ~ BesselJ(k,2)*(n+k)! (for fixed k and n -> infinity). Alec Mihailovs http://math.tntech.edu/alec/
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Alec Mihailovs