Number of sequences of n integers p(i) i=0..n-1 with 0<=p(i)<=3*i and -3<p(i)-p(i-1)<=3.

A180908

Number of sequences of n integers p(i) i=0..n-1 with 0<=p(i)<=3*i and -3<p(i)-p(i-1)<=3.

Terms

    a(0) =1a(1) =4a(2) =21a(3) =116a(4) =659a(5) =3802a(6) =22146a(7) =129838a(8) =764731a(9) =4519504a(10) =26778943a(11) =158989206a(12) =945437948a(13) =5629314106a(14) =33553133752a(15) =200164459648

External references