The sequence denoted by r_n used in the calculation of A323260.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =2a(5) =6a(6) =28a(7) =108a(8) =444a(9) =1792a(10) =7282a(11) =29538a(12) =119888a(13) =486512a(14) =1974392a(15) =8012464a(16) =32516266a(17) =131957670a(18) =535511468a(19) =2173215852a(20) =8819357908a(21) =35790772064a(22) =145246329946a(23) =589439543490