Number of -n..n arrays x(0..3) of 4 elements with zero sum, and adjacent elements not both strictly positive and not both strictly negative.

A199899

Number of -n..n arrays x(0..3) of 4 elements with zero sum, and adjacent elements not both strictly positive and not both strictly negative.

Terms

    a(0) =15a(1) =49a(2) =111a(3) =209a(4) =351a(5) =545a(6) =799a(7) =1121a(8) =1519a(9) =2001a(10) =2575a(11) =3249a(12) =4031a(13) =4929a(14) =5951a(15) =7105a(16) =8399a(17) =9841a(18) =11439a(19) =13201a(20) =15135a(21) =17249a(22) =19551a(23) =22049a(24) =24751a(25) =27665a(26) =30799a(27) =34161a(28) =37759a(29) =41601

External references