a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0 = s(n), |s(i) - s(i-1)| = 1 for i = 1,2; |s(i) - s(i-1)| <= 1 for i >= 3. Also a(n) = T(n,n), where T is the array defined in A024996.
A024997
a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0 = s(n), |s(i) - s(i-1)| = 1 for i = 1,2; |s(i) - s(i-1)| <= 1 for i >= 3. Also a(n) = T(n,n), where T is the array defined in A024996.
Terms
- a(0) =2a(1) =8a(2) =20a(3) =58a(4) =162a(5) =462a(6) =1318a(7) =3782a(8) =10886a(9) =31436a(10) =91016a(11) =264134a(12) =768094a(13) =2237640a(14) =6529284a(15) =19079574a(16) =55826166a(17) =163538472a(18) =479588844a(19) =1407813438a(20) =4136307798a(21) =12163015662a(22) =35793391662a(23) =105407889930a(24) =310620540202a(25) =915913267652
External references
- oeis: A024997