81820

Appears in sequences

• n times n+8 gives the concatenation of two numbers m and m+9.at n=5A116354
• a(n) = (10/11)*(2+9*(-10)^(n-1)).at n=5A165750
• a(n) is the smallest positive integer which can be represented as the sum of distinct nonzero n-gonal pyramidal numbers in exactly n ways, or 0 if no such integer exists.at n=27A350210