521136

Appears in sequences

• a(n) is the number of nonsymmetric patterns (no reflective, nor rotational symmetry) which may 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=18A060551
• Coefficients of the twisted K3 elliptic genus attached to the conjugacy class 1A in the Mathieu group M_24.at n=10A212301
• Number of length n+5 0..1 arrays with at most two downsteps in every n consecutive neighbor pairs.at n=29A256820