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

Terms

a(0) =1a(1) =1a(2) =5a(3) =20a(4) =83a(5) =337a(6) =1370a(7) =5559a(8) =22561a(9) =91554a(10) =371545a(11) =1507801a(12) =6118968a(13) =24832029a(14) =100773497a(15) =408959620a(16) =1659642439a(17) =6735171085a(18) =27332712458a(19) =110921780683a(20) =450143448069