87936

Appears in sequences

• Number of squarefree quaternary words of length n.at n=11A051041
• a(n) is the number of distinct (modulo geometric D3-operations) patterns which can be formed by an equilateral triangular arrangement of closely packed black and white cells satisfying the local matching rule of Pascal's triangle modulo 2, where n is the number of cells in each edge of the arrangement. The matching rule is such that any elementary top-down triangle of three neighboring cells in the arrangement contains either one or three white cells.at n=18A060553
• Triangular matrix T, read by rows, that satisfies: T^2 + T = SHIFTUP(T), also T^(n+1) + T^n = SHIFTUP(T^n - D*T^(n-1)) for all n, where D is a diagonal matrix with diagonal(D) = diagonal(T) = {1,2,3,...}.at n=21A103238
• Column 0 of triangular matrix T = A103238, which satisfies: T^2 + T = SHIFTUP(T) where diagonal(T)={1,2,3,...}.at n=6A103239
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, -1), (-1, -1, 1), (-1, 1, -1), (1, 0, 1), (1, 1, 0)}.at n=9A150177
• Number of n X 4 0..1 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.at n=21A223834