Number of positive walks with n steps {-3,-2,-1,1,2,3} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.
A276901
Number of positive walks with n steps {-3,-2,-1,1,2,3} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =9a(4) =34a(5) =159a(6) =730a(7) =3579a(8) =17762a(9) =90538a(10) =467796a(11) =2452727a(12) =12997554a(13) =69549847a(14) =375159290a(15) =2038068813a(16) =11140256754a(17) =61227097438a(18) =338140106124
External references
- oeis: A276901