Square chains: the number of permutations (reversals not counted as different) of the numbers 1 to n such that the sum of any two consecutive numbers is a square.
A071983
Square chains: the number of permutations (reversals not counted as different) of the numbers 1 to n such that the sum of any two consecutive numbers is a square.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =3a(9) =0a(10) =10a(11) =12a(12) =35a(13) =52a(14) =19a(15) =20a(16) =349a(17) =392a(18) =669a(19) =4041a(20) =17175a(21) =12960a(22) =14026a(23) =11889a(24) =29123a(25) =39550a(26) =219968a(27) =553694a(28) =2178103a(29) =5301127
External references
- oeis: A071983