A088877 Numbers k that are divisors of the number formed by concatenating (k-1), k and (k+1), in that order.

1, 3, 9, 11, 33, 111, 117, 143, 189, 231, 259, 273, 297, 333, 351, 407, 429, 481, 693, 777, 819, 1111, 1233, 1507, 2409, 3333, 4521, 7227, 7373, 11111, 26829, 27273, 33333, 81819, 100899, 101101, 108911, 111111, 123321, 128713, 129987, 142857

Offset: 1

Author

Chuck Seggelin, Oct 20 2003

Keywords

• base
• nonn

Comments

The sequence of numbers that divide the concatenation of k-1 and k+1 (A069871) is a subsequence of this sequence. - David Wasserman, Mar 26 2004

Examples

			a(7)=117 because 117 is a divisor of 116117118.
		

Links

• Paolo P. Lava, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A069871.

Programs

Mathematica

Select[Range[143000],MemberQ[Divisors[FromDigits[Flatten[ IntegerDigits/@ {#-1,#,#+1}]]],#]&] (* Harvey P. Dale, Aug 27 2020 *)