150920

Appears in sequences

• a(n) = ( (7 + sqrt(7))^n - (7 - sqrt(7))^n )/(2*sqrt(7)).at n=5A154248
• Integer areas of the intangents triangle of integer-sided triangles.at n=21A231740
• Smallest k such that A349410(k) = n or -1 if no such number exists.at n=13A349428