_i_series_terms

pmrf.math.bessel._i_series_terms(x)

Return the ascending-series terms of \(I_0\) and \(I_1\), and their sums.

Both series share the term \((x/2)^{2k}/(k!)^2\), accumulated as a running product so no factorial ever overflows; \(I_1\) weights it by \((x/2)/(k+1)\). The terms themselves are returned as well because the \(K\) series below weight the same ones by the harmonic numbers.