A307858 Composite numbers k with its divisors having the property that the last digit of every divisor is the same as the first digit of the next divisor.
121, 1111, 1207, 1331, 1441, 1661, 1991, 10201, 11231, 11341, 11561, 11671, 11917, 12001, 12221, 12661, 12767, 12881, 12937, 12991, 13211, 13231, 13541, 14201, 14311, 14531, 14641, 14971, 15191, 15251, 15851, 15961, 16181, 16291, 16621, 16841, 17161, 17281, 17309, 17611
Offset: 1
Examples
97663 is in the sequence because it is composite and its divisors, 1, 127, 769, 97663 have the property that the last digit of every divisor is the first digit of the next one.
Crossrefs
A306661 contains all these numbers plus prime numbers starting with 1.
Programs
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Mathematica
Select[Range@20000,PrimeQ@#==False&&And@@(Last@#[[1]]==First@#[[2]]&/@Partition[IntegerDigits/@Divisors@#,2,1])&]