24466267021domain: NAppears in sequencesA transformation of the Catalan sequence.at n=41A129110a(n) = C(n) + 1 - 0^n where C(n) = A000108(n).at n=21A141351Number of excursions of length n with Motzkin-steps avoiding the consecutive steps UH, HU, HD and DH.at n=42A329696