Number of subsets {x(1),x(2),...,x(k)} of {1,2,...,n} such that all differences |x(i)-x(j)| are distinct.

A143823

Number of subsets {x(1),x(2),...,x(k)} of {1,2,...,n} such that all differences |x(i)-x(j)| are distinct.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =7a(4) =13a(5) =22a(6) =36a(7) =57a(8) =91a(9) =140a(10) =216a(11) =317a(12) =463a(13) =668a(14) =962a(15) =1359a(16) =1919a(17) =2666a(18) =3694a(19) =5035a(20) =6845a(21) =9188a(22) =12366a(23) =16417a(24) =21787a(25) =28708a(26) =37722a(27) =49083a(28) =63921a(29) =82640

External references