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A335830 Decimal expansion of the sum of the reciprocals of the multiply-perfect numbers. 1
1, 2, 1, 4, 4, 0, 7, 6, 0, 8, 5, 9, 1, 4, 2, 7, 1, 9, 2, 9, 0, 6, 3, 8, 6, 3, 7, 3, 9, 0, 8, 2, 1, 8, 5, 6, 7, 8, 2, 2, 2, 7, 0, 6, 3, 1, 2, 8, 3, 4, 0, 8, 9, 0, 1, 1, 8, 6, 5, 6, 3, 9, 6, 2, 4, 2, 3, 9, 9, 3, 3, 9, 0, 1, 7, 8, 4, 4, 8, 4, 1, 6, 8, 0, 7, 8, 8, 8, 0, 0, 0, 8, 8, 8, 8, 6, 1, 9, 2, 9 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The first 18 terms were calculated by Bayless and Kinlaw (2015).

LINKS

Table of n, a(n) for n=1..100.

Jonathan Bayless and Paul Kinlaw, On repeated values of sigma and multiperfect numbers, Journal of Combinatorics and Number Theory, Vol. 7, No. 3 (2015), pp. 177-189.

FORMULA

Equals Sum_{k>=1} 1/A007691(k).

EXAMPLE

1.21440760859142719...

MATHEMATICA

multiPerfects = Cases[Import["https://oeis.org/A007691/b007691.txt", "Table"], {_, _}][[;; , 2]]; RealDigits[Total[1/multiPerfects], 10, 18][[1]]

CROSSREFS

Cf. A007691, A335118.

Sequence in context: A009477 A324658 A105568 * A004175 A136756 A214670

Adjacent sequences:  A335827 A335828 A335829 * A335831 A335832 A335833

KEYWORD

nonn,cons

AUTHOR

Amiram Eldar, Jun 25 2020

EXTENSIONS

More terms (computed using the b-file at A007691) from Jon E. Schoenfield, Jan 25 2021

STATUS

approved

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Last modified September 28 04:53 EDT 2021. Contains 347703 sequences. (Running on oeis4.)