Number of base 11 n-digit numbers with adjacent digits differing by one or less.

Terms

a(0) =1a(1) =11a(2) =31a(3) =89a(4) =257a(5) =745a(6) =2165a(7) =6303a(8) =18375a(9) =53625a(10) =156629a(11) =457795a(12) =1338779a(13) =3916897a(14) =11463989a(15) =33563035a(16) =98286811a(17) =287884769a(18) =843365485a(19) =2471005371a(20) =7240717539a(21) =21219286113a(22) =62189049541a(23) =182274146987a(24) =534268171099