OFFSET
1,1
FORMULA
Equals (1/8)(10 + 7 e^(1/4) sqrt(Pi) erf(1/2)).
Equals 1F1(2;1/2;1/4) . - R. J. Mathar, Jul 03 2024
EXAMPLE
2.2865189388213215074057263454433597027480...
MAPLE
hypergeom([2], [1/2], 1/4) ; evalf(%) ; # R. J. Mathar, Jul 03 2024
MATHEMATICA
s = Sum[(k + 1)!/(2 k)!, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Clark Kimberling, Apr 27 2024
STATUS
approved