Number of excursions of length n on the upper-right part of the hexagonal lattice.

A057648

Number of excursions of length n on the upper-right part of the hexagonal lattice.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =2a(4) =13a(5) =34a(6) =158a(7) =594a(8) =2665a(9) =11558a(10) =53320a(11) =247488a(12) =1181266a(13) =5708884a(14) =28049474a(15) =139417402a(16) =701063005a(17) =3559326294a(18) =18233244530a(19) =94140532624a(20) =489573775236

External references