A335007 Decimal expansion of 2*(gamma - zeta'(2)/zeta(2)) - 1, where gamma is the Euler-Mascheroni constant.

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

Offset

1,2

Links

Table of n, a(n) for n=1..87.

Eckford Cohen, The number of unitary divisors of an integer, The American Mathematical Monthly, Vol. 67, No. 9 (1960), pp. 879-880.

Formula

Equals lim_{k->oo} ((zeta(2)/k)*A064608(k) - log(k)) where A064608 is the partial sums of the number of unitary divisors (A034444).

Equals 2*A001620 + 2*A073002/A013661 - 1 = 2*A335006 - 1.

Example

1.2943533159921313340127529002042648668912832334937...

Mathematica

RealDigits[2*EulerGamma - 2*Zeta'[2]/Zeta[2] - 1, 10, 100][[1]]

Prog

(PARI) 2*Euler - 2*zeta'(2)/zeta(2) - 1 \\ Michel Marcus, May 19 2020

Crossrefs

Cf. A001620 (gamma), A013661 (zeta(2)), A034444, A064608, A073002 (-zeta'(2)), A147533, A335006.

Sequence in context: A011067 A135008 A200014 * A248968 A097881 A019758

Adjacent sequences: A335004 A335005 A335006 * A335008 A335009 A335010

Keyword

nonn,cons

Author

Amiram Eldar, May 19 2020

Status

approved