572975domain: NAppears in sequencesNonsquarefree "year numbers" (numbers n such that phi(n) = 2*phi(sigma(n)): A137815).at n=21A137816Number of reduced words of length n in the Weyl group B_25.at n=6A161932Number of reduced words of length n in the Weyl group D_25.at n=6A162367