Number of n X 4 nonnegative integer arrays with upper left 0 and every value within 3 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.

A252824

Number of n X 4 nonnegative integer arrays with upper left 0 and every value within 3 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.

Terms

    a(0) =8a(1) =53a(2) =340a(3) =1920a(4) =9075a(5) =36292a(6) =125892a(7) =387849a(8) =1082111a(9) =2777103a(10) =6637625a(11) =14922949a(12) =31813809a(13) =64737785a(14) =126429330a(15) =238046837a(16) =433778614a(17) =767506845a(18) =1322268502a(19) =2223460226a(20) =3656986483a(21) =5893853502a(22) =9323072932a(23) =14495166797a(24) =22179067861

External references