1600370

Appears in sequences

• Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having two adjacent 1's and two adjacent 0's, with rows and columns of the latter in lexicographically nondecreasing order.at n=23A227329
• Numbers k such that Sum_{i=1..k} i' == 0 (mod k), where i' is the arithmetic derivative of i.at n=10A229501