71426

Appears in sequences

• Number of (n+1)X(7+1) 0..2 arrays with the upper median of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one.at n=10A237636
• Start with a single pentagon; at n-th generation add a pentagon at each expandable vertex; a(n) is the sum of all label values at n-th generation. (See comment for construction rules.)at n=22A247619