Number of n X 4 nonnegative integer arrays with upper left 0 and every value within 2 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.

A252816

Number of n X 4 nonnegative integer arrays with upper left 0 and every value within 2 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) =7a(1) =40a(2) =187a(3) =684a(4) =2078a(5) =5490a(6) =13015a(7) =28299a(8) =57338a(9) =109549a(10) =199168a(11) =347035a(12) =582831a(13) =947837a(14) =1498290a(15) =2309416a(16) =3480225a(17) =5139158a(18) =7450681a(19) =10622926a(20) =14916484a(21) =20654460a(22) =28233905a(23) =38138745a(24) =50954332a(25) =67383747a(26) =88265990a(27) =114596197

External references