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A371942
Decimal expansion of Sum_{k>=0} (k+2)! / (2k+1)!.
1
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, 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, 1, 4, 9, 8, 8, 0, 2, 0, 3, 3, 6, 1, 1, 5, 7, 1, 0, 1
OFFSET
1,1
FORMULA
Equals (1/16)*(22 + 25*e^(1/4)*sqrt(Pi)*erf(1/2)).
Equals 2* 1F1(3;3/2;1/4) . - R. J. Mathar, Aug 02 2024
EXAMPLE
3.22592667646664554893879704543457089776442691317...
MATHEMATICA
s = Sum[(k + 2)!/(2 k+1)!, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d]]
CROSSREFS
Cf. A371947.
Sequence in context: A058608 A112196 A021035 * A259967 A007567 A093055
KEYWORD
nonn,cons
AUTHOR
Clark Kimberling, Apr 28 2024
STATUS
approved