A variant of the Titius-Bode Law

the study of the geometric distribution of the planets invariably mentions the titius bode law as an attempt to classify their heliocentric distances through a succession of integer numbers. with the discovery of more planetary objects better support is given to the basic principie of the law through their orbital parameters. we briefly refer to a classification of orbital parameters using kepler's proportionality parameter and discuss the problem of applying the tb law to extrasolar systems. we also review work by various authors who have proposed functions which reproduce with some degree of certainty the planetary heliocentric distances, and we compare them to our variant of the titius-bode law.