31509

Appears in sequences

• Numbers n such that n | 3^n + 2^n + 1^n.at n=24A056645
• Expansion of (1-x)/(1-3*x-3*x^2-2*x^3).at n=8A077837
• Number of 4 X n 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.at n=18A229447
• Numbers k such that pi(k) is the concatenation of distinct prime factors of k, in increasing order.at n=2A251361
• The number of distinct positions on an infinite chessboard reachable by the (2,3)-leaper (or zebra) in at most n moves.at n=31A297740
• a(n) is the least positive number k such that n is the greatest m such that k is a quadratic residue mod prime(i) for i=1..m and {k mod prime(i): i=1..m} are all distinct.at n=7A385050