This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A365538 #32 Feb 07 2024 20:38:13 %S A365538 1,1,2,0,2,2,0,0,2,2,4,0,0,0,0,0,2,2,4,0,4,4,0,0,0,0,0,0,0,0,0,0,2,2, %T A365538 4,0,4,4,0,0,4,4,8,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 %N A365538 a(0) = 1; otherwise, for i >= 0, a(4i+0) = a(4i+1) = a(2i), a(4i+2) = 2*a(2i+1), a(4i+3) = 0. %C A365538 Related to a model of X-chromosome inheritance: %C A365538 The two X chromosomes of a female are inherited one from each parent, while the X chromosome of a male is always inherited from his mother. Thus, the probability distribution of inheritance from the parents (mother, father) is (0.5, 0.5) for a female and (1, 0) for a male. For the inheritance of any X-chromosome of a female from the 2^i ancestors of the i-th generation before (right to left on an ahnentafel), the distribution is given by the first 2^i terms of the sequence, divided by 2^i. For example, the X-chromosome of a man, which was inherited from his mother, was inherited from his mother's 16 great-great-grandparents with probabilities 1/16, 1/16, 1/8, 0, 1/8, 1/8, 0, 0, 1/8, 1/8, 1/4, 0, 0, 0, 0, 0. %H A365538 Roland Kneer, <a href="/A365538/b365538.txt">Table of n, a(n) for n = 0..10000</a> %F A365538 This sequence regarded as a triangle with rows of lengths 1, 1, 2, 4, 8, 16, ...: %F A365538 1; %F A365538 1; %F A365538 2, 0; %F A365538 2, 2, 0, 0; %F A365538 2, 2, 4, 0, 0, 0, 0, 0; %F A365538 2, 2, 4, 0, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0; %F A365538 ... %Y A365538 Cf. A280873, A003754. %Y A365538 Positions of 0's: A004780 (complement of A003714). %K A365538 nonn,tabf,easy %O A365538 0,3 %A A365538 _Roland Kneer_, Oct 23 2023