Number of interior vertices formed by drawing the lines connecting any two of the 2*(n+2) perimeter points of a 3 X (n+1) square grid.

A331767

Number of interior vertices formed by drawing the lines connecting any two of the 2*(n+2) perimeter points of a 3 X (n+1) square grid.

Terms

    a(0) =7a(1) =29a(2) =89a(3) =201a(4) =387a(5) =641a(6) =1067a(7) =1599a(8) =2305a(9) =3233a(10) =4431a(11) =5855a(12) =7721a(13) =9853a(14) =12369a(15) =15477a(16) =19093a(17) =23141a(18) =28073a(19) =33557a(20) =39699a(21) =46773a(22) =54815a(23) =63681a(24) =73825a(25) =84833a(26) =97005a(27) =110579a(28) =125587a(29) =141733

External references