a(n) = A261234(n) - A261237(n).

Terms

a(0) =0a(1) =1a(2) =3a(3) =7a(4) =16a(5) =40a(6) =104a(7) =279a(8) =758a(9) =2071a(10) =5678a(11) =15609a(12) =43035a(13) =119139a(14) =331616a(15) =928572a(16) =2614743a(17) =7396880a(18) =20999683a(19) =59784414a(20) =170615755a(21) =488073987a(22) =1399625614a(23) =4023315793a(24) =11590737827a(25) =33452982391