A343187 Decimal expansion of Sum_{k>=1} 1/af(k), where af is the alternating factorial.

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

Offset

1,1

Links

Table of n, a(n) for n=1..105.

Example

2.2644055179325317... = 1/1 + 1/1 + 1/5 + 1/19 + 1/101 +....

Maple

evalf(sum(1/sum((-1)^(k - i)*i!, i = 1 .. k), k = 1 .. infinity));

Prog

(PARI) f(n) = sum(k=0, n-1, (-1)^k*(n-k)!); \\ A005165
suminf(n=1, 1/f(n)) \\ Michel Marcus, Apr 07 2021

Crossrefs

Cf. A005165 (alternating factorial).

Sequence in context: A193819 A356790 A182786 * A009279 A059943 A264695

Adjacent sequences: A343184 A343185 A343186 * A343188 A343189 A343190

Keyword

cons,nonn

Author

Andrzej Kukla, Apr 07 2021

Status

approved