>>621
どうも。スレ主です。
ありがとう
こんなのもあるね
https://en.wikipedia.org/wiki/Euler%E2%80%93Mascheroni_constant
Euler?Mascheroni constant

Series expansions
In general,
γ＝lim(n→∞)1+1/2+1/3+…+1/n-log(n+α)≡lim(n→∞)γn(α)
for any α > −n .
However, the rate of convergence of this expansion depends significantly on α .
In particular, γn(1/2) exhibits much more rapid convergence than the conventional expansion γn(0).[7][8]
This is because
1/{2(n+1)} < γn(0) - γ < 1/(2n)
while
1/{24(n+1)^2} < γn(1/2) < 1/{24(n)^2}
Even so, there exist other series expansions which converge more rapidly than this; some of these are discussed below.