This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A060507 #14 May 08 2018 15:11:55 %S A060507 1,72,3456,746496,214990848,1719926784,743008370688,53496602689536, %T A060507 10271347716390912,6655833320221310976,958439998111868780544, %U A060507 23002559954684850733056 %N A060507 Denominators of the asymptotic expansion of the Airy function Ai(x). %C A060507 The series arises in the asymptotic expansion of the Airy function A(x) for large |x| as Ai(x)~pi^(-1/2)/2*x^(-1/4)*exp(-z)*sum((-1)^k*c(k)*z^(-k),k=0..infinity), where z=2/3*x^(3/2). a(k) is the denominator of the fully canceled c(k). %D A060507 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings). %H A060507 M. Abramowitz and I. A. Stegun, eds., <a href="http://www.convertit.com/Go/ConvertIt/Reference/AMS55.ASP">Handbook of Mathematical Functions</a>, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy]. %H A060507 NIST's Digital Library of Mathematical Functions, <a href="http://dlmf.nist.gov/9.7#ii">Airy and Related Functions (Poincaré-Type Expansions)</a> by Frank W. J. Olver. %F A060507 a(k)=denom(product((2*l+1), l=k..3*k-1)/216^k/k!). %e A060507 a(2) = 3456 because for k=2, product((2*l+1),l=k..3*k-1)/216^k/k! = 385/3456 and we take the denominator of the fully canceled fraction. %t A060507 a[ n_] := If[ n<0, 0, Denominator[ Product[k, {k, 1, 6 n - 1, 2}] / n! / 216^n]] (* _Michael Somos_, Oct 14 2011 *) %Y A060507 Cf. A060506, A014402, A014403. %K A060507 easy,frac,nonn %O A060507 0,2 %A A060507 Michael Praehofer (praehofer(AT)ma.tum.de), Mar 22 2001