172267

Appears in sequences

• a(n) is the number of n-cell polyiamonds (triangular polyominoes) with perimeter n+2.at n=15A131481
• Inverse Euler transform of 2 - A195981.at n=15A206000
• a(n) = k is a number such that A007535(k), the smallest pseudoprime to base k ( > k), is the n-th Carmichael number.at n=21A293563