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

Author

Andrzej Kukla, Apr 07 2021

Keywords

• cons
• nonn

Examples

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

Crossrefs

Cf. A005165 (alternating factorial).

Programs

Maple

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

PARI

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