1/4 the number of arrangements of 4 nonzero numbers x(i) in -n..n with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero.

A189953

1/4 the number of arrangements of 4 nonzero numbers x(i) in -n..n with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero.

Terms

    a(0) =4a(1) =22a(2) =63a(3) =159a(4) =306a(5) =542a(6) =889a(7) =1350a(8) =1940a(9) =2734a(10) =3670a(11) =4819a(12) =6238a(13) =7852a(14) =9688a(15) =11986a(16) =14411a(17) =17274a(18) =20412a(19) =23919a(20) =27900a(21) =32443a(22) =37028a(23) =42280a(24) =48028a(25) =54459a(26) =60919a(27) =68477a(28) =76078a(29) =84753

External references