cp's OEIS Frontend

A252898 Decimal expansion of lim_{n->infinity} -FractionalPart[Zeta'(1+1/n)] or -FractionalPart[Zeta'(1-1/n)], where Zeta' is the first derivative of the Riemann zeta function.

%I A252898 #43 May 28 2025 20:03:20
%S A252898 9,2,7,1,8,4,1,5,4,5,1,6,3,2,3,2,7,5,1,3,9,4,1,3,6,2,4,1,2,5,0,9,8,6,
%T A252898 8,0,8,6,2,2,6,3,6,6,1,6,6,5,6,6,2,0,4,7,4,0,0,9,9,3,4,4,0,2,5,8,5,9,
%U A252898 8,5,6,6,4,2,8,4,8,8,5,1,5,1,2,1,9,1,3,0,7,1,7,5,5,1,5,5,9,8,5,3,9,5,9,2,2,7,9
%N A252898 Decimal expansion of lim_{n->infinity} -FractionalPart[Zeta'(1+1/n)] or -FractionalPart[Zeta'(1-1/n)], where Zeta' is the first derivative of the Riemann zeta function.
%C A252898 Zeta'(x) -> negative infinity as x -> 1, from above and below.
%C A252898 When 1 is approached using arguments of (1+1/n) or (1-1/n), its fractional part converges to this constant.
%C A252898 The Euler-Mascheroni constant is the fractional part as x->1 for Zeta(x), but with a different symmetry approaching 1 from above vs. below. See A001620 and below.
%C A252898 The integer part of Zeta'(1 + 1/n) or Zeta'(1 - 1/n)  =  -(n^2 - 1).
%C A252898 Corresponding constants, as taken from the fractional part, exist for the higher order derivatives of the Riemann zeta as x->1 with these arguments. The list below shows converged values up to the 10th derivative approaching 1 from above, using
%C A252898 x = 1 + 1/n, as n -> infinity, with signs:
%C A252898   Derivative[1] = -0.9271841545163232751394136...  (this entry)
%C A252898   Derivative[2] =  0.9903096368071276815154696...
%C A252898   Derivative[3] = -0.0020538344203033458661600...
%C A252898   Derivative[4] =  0.0023253700654673000057468...
%C A252898   Derivative[5] = -0.0007933238173010627017533...
%C A252898   Derivative[6] =  0.9997612306545698003901275...
%C A252898   Derivative[7] = -0.9994727104329422489539259...
%C A252898   Derivative[8] =  0.9996478766461969604903979...
%C A252898   Derivative[9] = -0.9999656052255819119518220...
%C A252898   Derivative[10]=  0.0002053328149090647946837...
%C A252898 Even order derivatives, D[2m], (e.g., 2nd, 4th, 6th, ...) have different fractional values when approaching 1 from below equal to: -(1-D[2m]). The same is true for D[0], or Zeta itself.
%C A252898 The integer sequences associated with the integer part, with x ->1 from above and starting with the argument x= 2 = 1+1/n, hence n = 1 to infinity, are:
%C A252898   Derivative[1] =  -(n^2-1)
%C A252898   Derivative[2] =   (2!*n^3-1)
%C A252898   Derivative[3] =  -(3!*n^4)
%C A252898   Derivative[4] =   (4!*n^5)
%C A252898   Derivative[5] =  -(5!*n^6)
%C A252898   Derivative[6] =   (6!*n^7-1), except at n=1, where value = 720 with fract ~0.0001
%C A252898   Derivative[7] =  -(7!*n^8-1)
%C A252898   Derivative[8] =   (8!*n^9-1)
%C A252898   Derivative[9] =  -(9!*n^10-1)
%C A252898   Derivative[10] =  (10!*n^11)
%C A252898 Thus, rounding the m-th derivative of Zeta(x) at x=2 (n=1) gives (-1)^m * m! for m>=1. See A073002.
%F A252898 Limit_{n -> infinity} -FractionalPart[Zeta'(1+1/n)]
%F A252898 Limit_{n -> infinity} -FractionalPart[Zeta'(1-1/n)]
%F A252898 Equals 1 - A082633. - _Alois P. Heinz_, Dec 30 2014
%e A252898 0.9271841545163232751394136...
%p A252898 s:= convert(evalf(1+gamma(1), 140), string):
%p A252898 seq(parse(s[n+2]), n=0..110);  # _Alois P. Heinz_, Dec 30 2014
%t A252898 FractionalPart[N[Derivative[1][Zeta][
%t A252898    1 + 1/(1000000000000000000000000000000000000000000000000000000000000)], 400]]
%Y A252898 Cf. A001620, A073002, A082633.
%K A252898 nonn,cons
%O A252898 0,1
%A A252898 _Richard R. Forberg_, Dec 24 2014
%E A252898 More digits from _Alois P. Heinz_, Dec 30 2014