a(1) = 1, a(2) = 21; for n>2, a(n) is the least number whose neighboring digit difference forms a(n-1) such that a(n+1) also exists.

A110400

a(1) = 1, a(2) = 21; for n>2, a(n) is the least number whose neighboring digit difference forms a(n-1) such that a(n+1) also exists.

Terms

    a(0) =1a(1) =21a(2) =132a(3) =1031a(4) =10032a(5) =100031a(6) =1000032a(7) =10000031a(8) =100000032a(9) =1000000031a(10) =10000000032a(11) =100000000031

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