T(n, 2n-10), T given by A027960.

Terms

a(0) =1a(1) =4a(2) =11a(3) =29a(4) =76a(5) =199a(6) =518a(7) =1324a(8) =3278a(9) =7784a(10) =17643a(11) =38138a(12) =78753a(13) =155793a(14) =296248a(15) =543333a(16) =964239a(17) =1660748a(18) =2783499a(19) =4550843a(20) =7273394a(21) =11385571a(22) =17485634a(23) =26385946a(24) =39175444a(25) =57296576a(26) =82639259a(27) =117654736a(28) =165492559