a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is an integer, s(0) = 0, |s(1)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2, s(n) = 4. Also a(n) = T(n,n-4), where T is the array defined in A025177.
A025182
a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is an integer, s(0) = 0, |s(1)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2, s(n) = 4. Also a(n) = T(n,n-4), where T is the array defined in A025177.
Terms
- a(0) =1a(1) =4a(2) =16a(3) =56a(4) =189a(5) =616a(6) =1968a(7) =6192a(8) =19272a(9) =59488a(10) =182468a(11) =556920a(12) =1693146a(13) =5131296a(14) =15511344a(15) =46791072a(16) =140905197a(17) =423709956a(18) =1272596136a(19) =3818355464a(20) =11447074309a(21) =34292702840a(22) =102670377120a(23) =307230479920a(24) =918951019155
External references
- oeis: A025182