Number of truncated ST-pairs O(q^n).

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =11a(5) =15a(6) =26a(7) =41a(8) =67a(9) =96a(10) =138a(11) =197a(12) =300a(13) =431a(14) =636a(15) =893a(16) =1258a(17) =1723a(18) =2447a(19) =3425a(20) =4962a(21) =6839a(22) =10000a(23) =13989a(24) =21383a(25) =30781a(26) =48292a(27) =70456a(28) =110214a(29) =159686