Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #10 Mar 12 2019 13:47:51
%S 2,7,126,49025,11038230966,634456062604213659925,
%T 3415859231992196603487034219242943862111730,
%U 128354131452658375331590552350866791928171509211813123694476377780255927632036301443101
%N The "word binomial coefficient" of (mu^(n+1) (0) | mu^n (0)), where mu is the Thue-Morse morphism.
%C Here mu(0) = 01 and mu(1) = 10, and mu^n(a) = mu(mu(mu... (a) ...))) (n times). The "word binomial coefficient" (x|y) is the number of ways that y can be a (scattered) subsequence of x.
%e For n = 2, a(n) enumerates the 7 ways 0110 can be a subsequence of 01101001.
%Y Cf. A010060, A323598.
%K nonn
%O 0,1
%A _Jeffrey Shallit_, Jan 18 2019