OFFSET
0,1
FORMULA
Equals e - 2*A143820.
Equals Sum_{n>=0} (-1)^(2^((n-1) mod 3) mod 2) / n! = e/3 - 4*sin(sqrt(3)/2 - Pi/6) / (3*sqrt(e)).
Equals Sum_{n>=0) 1/(3*n)! - 1/(3*n+1)! + 1/(3*n+2)!. - Michal Paulovic, Aug 19 2023
EXAMPLE
0.63455111826122554275761424130960772236307995025163265587548911687697314...
MAPLE
Digits:=105: evalf(sum(1/(3*n)!-1/(3*n+1)!+1/(3*n+2)!, n=0..infinity)); # Michal Paulovic, Aug 20 2023
MATHEMATICA
RealDigits[E/3 - (4*Sin[Sqrt[3]/2-Pi/6])/(3*Sqrt[E]), 10, 105][[1]]
PROG
(PARI) suminf(n=0, 1/(3*n)!-1/(3*n+1)!+1/(3*n+2)!) \\ Michal Paulovic, Aug 20 2023
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Peter McNair, Aug 19 2023
STATUS
approved