Number of nX7 0..1 arrays with rows and columns lexicographically nondecreasing read forwards, and nonincreasing read backwards.

A201374

Number of nX7 0..1 arrays with rows and columns lexicographically nondecreasing read forwards, and nonincreasing read backwards.

Terms

    a(0) =2a(1) =8a(2) =44a(3) =280a(4) =2016a(5) =15574a(6) =115168a(7) =728078a(8) =3793342a(9) =16517460a(10) =61759798a(11) =203474642a(12) =603403128a(13) =1638153030a(14) =4126393250a(15) =9747403504a(16) =21778931370a(17) =46349684784a(18) =94496712184a(19) =185448946836a(20) =351735813872a(21) =646956766742

External references