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 A213053 #27 Jan 23 2025 22:08:47 %S A213053 2,1,7,2,3,3,6,2,8,2,1,1,2,2,1,6,5,7,4,0,8,2,7,9,3,2,5,5,6,2,4,7,0,7, %T A213053 3,4,2,2,3,0,4,4,9,1,5,4,3,5,5,8,7,4,8,2,3,6,5,4,4,9,0,2,7,7,1,4,5,0, %U A213053 5,3,4,3,5,8,9,0,6,3,2,2,9,1,8,5,5,6,8,0,5,0,6,5,3,9,2,3,5,4,9,5,1,5,2,0,1 %N A213053 Decimal expansion of the absolute minimum of sinc(x) = sin(x)/x (negated). %C A213053 Minimum value of the first negative lobe of sinc(x), attained for abs(x) = A115365. %C A213053 The involute of the unit circle which starts at (1,0) crosses the x-axis for the first time at x = 1/a. - _Álvar Ibeas_, Jul 28 2017 %F A213053 Equals -1 / sqrt(1 + A115365^2) = cos(A115365). - _Álvar Ibeas_, Jul 28 2017 %e A213053 min[real x](sinc(x)) = -0.2172336282112216574082... %t A213053 digits = 105; NMinimize[ Sinc[x], x, WorkingPrecision -> digits+5] // First // RealDigits[#, 10, digits]& // First (* _Jean-François Alcover_, Mar 05 2013 *) %t A213053 RealDigits[Sinc[BesselJZero[3/2, 1]], 10, 100][[1]] (* _Vladimir Reshetnikov_, May 13 2016 *) %o A213053 (PARI) y=solve(x=4,4.5,tan(x)-x);-sin(y)/y \\ _Charles R Greathouse IV_, Jun 10 2012 %o A213053 (PARI) -sinc(besseljzero(3/2,1)) \\ _Charles R Greathouse IV_, Jan 23 2025 %Y A213053 Cf. A115365. %K A213053 nonn,cons %O A213053 0,1 %A A213053 _Stanislav Sykora_, Jun 09 2012