20239

Appears in sequences

• Numbers whose base-4 representation contains exactly three 0's and four 3's.at n=29A045080
• Rhombi (in 3 different orientations) in a rhombus with 60-degree acute angles.at n=36A052153
• Numbers which are the sum of the squares of seven consecutive primes.at n=12A133562
• Transform of the finite sequence (1, 0, -1, 0, 1) by the T_{0,0} transform (see link).at n=13A159348
• Number of 4 X n 0..1 arrays with rows nondecreasing and antidiagonals unimodal.at n=13A224135
• Number of ways to stack n triangles symmetrically (pointing upwards or downwards depending on row parity).at n=33A316585