101210

Appears in sequences

• Smallest multiple of the n-th prime beginning and ending in n with a(1)=a(3)=0.at n=9A078212
• Catalan paths: numbers starting with 1 and ending with 0 where each digit is nonnegative and adjacent digits differ by 1.at n=4A079214
• Lexicographically earliest increasing sequence with property that in the concatenation of its terms every pair of consecutive digits differs by 1.at n=18A098766