8914800domain: NAppears in sequencesa(n) = binomial(2*n, n) mod binomial(2*n-2, n-1).at n=12A024483Expansion of e.g.f. Bessel_I(2,2x) + 2*Bessel_I(3,2x) + Bessel_I(4,2x).at n=25A116385Oscillating orbitals over n sectors (nonpositive values indicating there exist none).at n=26A232500a(n) = (n-1)*Catalan(n).at n=13A276666