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) = 1. Also a(n) = T(n,n-1), where T is the array defined in A024996.
A024998
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) = 1. Also a(n) = T(n,n-1), where T is the array defined in A024996.
Terms
- a(0) =1a(1) =0a(2) =3a(3) =6a(4) =19a(5) =52a(6) =150a(7) =428a(8) =1232a(9) =3552a(10) =10275a(11) =29790a(12) =86559a(13) =251980a(14) =734773a(15) =2145822a(16) =6275145a(17) =18373296a(18) =53856153a(19) =158025186a(20) =464112297a(21) =1364247180a(22) =4013353932a(23) =11815188000a(24) =34807249134a(25) =102606325136a(26) =302646363725a(27) =893175905778
External references
- oeis: A024998