A371942 - OEIS

%I #12 Aug 02 2024 12:23:01

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

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

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

%N Decimal expansion of Sum_{k>=0} (k+2)! / (2k+1)!.

%F Equals (1/16)*(22 + 25*e^(1/4)*sqrt(Pi)*erf(1/2)).

%F Equals 2* 1F1(3;3/2;1/4) . - _R. J. Mathar_, Aug 02 2024

%e 3.22592667646664554893879704543457089776442691317...

%t s = Sum[(k + 2)!/(2 k+1)!, {k, 0, Infinity}]

%t d = N[s, 100]

%t First[RealDigits[d]]

%Y Cf. A371947.

%K nonn,cons

%O 1,1

%A _Clark Kimberling_, Apr 28 2024