A336334 Decimal expansion of Sum_{n>=1} phi(n)/n!, where phi(n) is the Euler totient function A000010.

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

Offset: 1

Author

Hugo Pfoertner, Jul 22 2020

Keywords

• nonn
• cons

Comments

The following comment is provided in A000010: Sum_{n>=1} a(n)/n! = 1.954085357876006213144... This sum is referenced in Plouffe's inverter. - Alexander R. Povolotsky, Feb 02 2013

This constant is irrational (Erdős and Straus, 1974). - Amiram Eldar, Jul 04 2021

Examples

			1.9540853578760062131445948611471495403706727701869610608298777207887...
		

Links

• Paul Erdős and Ernst G. Straus, On the irrationality of certain series, Pacific journal of mathematics, Vol. 55, No. 1 (1974), pp. 85-92.

Crossrefs

Cf. A000010.

Programs

PARI

suminf(k=1,eulerphi(k)/k!)