399377

Appears in sequences

• Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 5-point zee 1,1 2,1 2,2 2,3 3,3 in any orientation.at n=15A146069
• Numbers k such that k and the k-th triangular number T(k) = k*(k+1)/2 have only odd digits.at n=17A347475