199001

Appears in sequences

• a(n) = a(n-1) + a(n-2) + 1, with a(0) = 1 and a(1) = 9.at n=22A022323
• Consider any concatenation of the type n = concat(a,b). Sequence lists numbers whose reverses are the sum of the products of some of such couples a and b.at n=15A281555
• Centered 10-gonal numbers which are sphenic numbers.at n=13A368426