87434

Appears in sequences

• Engel expansion of hz = limit_{k -> infinity} 1 + k - Sum_{j = -k..k} exp(-2^j).at n=21A159835
• Triangle read by rows: T(n,k) is the number of up-down permutations of {1,2,...,n} having genus k (see first comment for definition of genus).at n=57A178516
• Numbers k such that 403*2^k+1 is prime.at n=40A323101