99980

Appears in sequences

• Composite numbers k such that (k+1)*sigma(k) is a perfect square.at n=17A073586
• Numbers n such that every digit of both n and n^2 contains a loop (only digits 0,4,6,8,9 in n and n^2).at n=30A107626
• Numbers k such that k and k^2 use only the digits 0, 4, 6, 8 and 9.at n=31A136956
• Lengths of loops in the P2 Penrose tiling.at n=10A215878
• a(n) = n^5 - 2n.at n=10A242436