A086728 Decimal expansion of Sum_{m>=0} 1/(6*m+2)^2.

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

Offset

0,1

References

László Fejes Tóth, Lagerungen in der Ebene, auf der Kugel und im Raum, 2nd. ed., Springer-Verlag, Berlin, Heidelberg, 1972; see p. 213.

Links

Table of n, a(n) for n=0..98.

Formula

Equals A214550 divided by 4. - R. J. Mathar, Sep 15 2012

From Amiram Eldar, Jun 26 2026: (Start)

Equals Sum_{m>=0} 1/A016934(m).

Equals psi'(1/3)/36, where psi' is the first derivative of the digamma function.

Equals Integral_{x=0..1} x*log(x)/(x^6 - 1) dx. (End)

Example

0.28043325348408594671644455833034767668108066998002...

Mathematica

RealDigits[ PolyGamma[1, 1/3]/36, 10, 99] // First (* Jean-François Alcover, Feb 12 2013 *)

Prog

(PARI) psi'(1/3)/36 \\ Amiram Eldar, Jun 26 2026

Crossrefs

Cf. A016934, A086722-A086731, A214550.

Sequence in context: A244122 A021785 A136664 * A118292 A160584 A191334

Adjacent sequences: A086725 A086726 A086727 * A086729 A086730 A086731

Keyword

nonn,cons,changed

Author

N. J. A. Sloane, Jul 31 2003

Status

approved