171718

Appears in sequences

• Number of nX4 0..1 arrays with every element equal to 1, 2, 4, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=9A301357
• Smallest positive integer that has exactly n representations of the form 1 + p1 * (1 + p2* ... * (1 + p_j)...), where [p1, ..., p_j] is a (possibly empty) list of distinct primes.at n=21A317385
• Centered heptagonal numbers which are sphenic numbers.at n=27A360183