A336334 - OEIS

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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

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OFFSET

1,2

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

LINKS

Table of n, a(n) for n=1..85.

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

EXAMPLE

1.9540853578760062131445948611471495403706727701869610608298777207887...

PROG

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

CROSSREFS

Cf. A000010.

Sequence in context: A182125 A010542 A013678 * A139604 A104139 A244648

Adjacent sequences: A336331 A336332 A336333 * A336335 A336336 A336337

KEYWORD

nonn,cons

AUTHOR

Hugo Pfoertner, Jul 22 2020

STATUS

approved