a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, |s(i) - s(i-1)| = 1 for i = 1,2; |s(i) - s(i-1)| <= 1 for i >= 3, s(n) = 4. Also a(n) = T(n,n-4), where T is the array defined in A024996.
A026071
a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, |s(i) - s(i-1)| = 1 for i = 1,2; |s(i) - s(i-1)| <= 1 for i >= 3, s(n) = 4. Also a(n) = T(n,n-4), where T is the array defined in A024996.
Terms
- a(0) =1a(1) =3a(2) =12a(3) =40a(4) =133a(5) =427a(6) =1352a(7) =4224a(8) =13080a(9) =40216a(10) =122980a(11) =374452a(12) =1136226a(13) =3438150a(14) =10380048a(15) =31279728a(16) =94114125a(17) =282804759a(18) =848886180a(19) =2545759328a(20) =7628718845a(21) =22845628531a(22) =68377674280a(23) =204560102800a(24) =611720539235
External references
- oeis: A026071