%N Absolute differences of A129198.
%C This sequence is known to be a permutation of positive integers, along with its parent sequence (A129198).
%C In the paper of Slater and Velez it is shown that both this sequence and its parent are permutations of positive integers.
%H P. J. Slater and W. Y. Velez, <a href="https://projecteuclid.org/euclid.pjm/1102811644">Permutations of the Positive Integers with Restrictions on the Sequence of Differences</a>, Pacific J. Math., 71, 1977.
%H William Y. Velez, <a href="https://doi.org/10.1016/0012-365X(92)90724-T">Research problems 159-160</a>, Discrete Math 110 (1992), pp. 301-302.
%Y This is the absolute difference of A129198, cf. A081145.
%A Ferenc Adorjan (fadorjan(AT)freemail.hu or ferencadorjan(AT)gmail.com), Apr 04 2007