A372339 Decimal expansion of Sum_{k>=0} (-1)^k * (k+2) / ((k+1)*(2*k)!).

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

Offset

1,2

Links

Table of n, a(n) for n=1..86.

Formula

Equals -2 + 3*cos(1) + 2*sin(1).

Example

1.3038488872202121655078144655895278104420573...

Mathematica

s = Sum[(-1)^k (k + 2)/((k + 1) (2 k)!), {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d]]

Prog

(PARI) 3*cos(1) + 2*sin(1) - 2 \\ Charles R Greathouse IV, Jun 08 2026

Crossrefs

Cf. A049469, A049470, A372338.

Sequence in context: A154853 A139214 A010030 * A197270 A117940 A099093

Adjacent sequences: A372336 A372337 A372338 * A372340 A372341 A372342

Keyword

nonn,cons,changed

Author

Clark Kimberling, Apr 28 2024

Status

approved