HP49/50 summation weirdness

[rawi]

Your results are confirmed with HP50g.
It seems as if in summation lnp1(x) is transformed to ln(1+x), but not in programs.

If I do '∑(N=1.,100.,LN(1.-(1./(100.*SQ(n)))))' EVAL I get -1.64042967882E-2,
so there is no change compared to using lnp1(x)

If I do
« 0. 1. 100. FOR N
N SQ 100. * INV NEG 1 + LN +
NEXT »
I get -1.64042967882E-2.