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

1,2

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

Links

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

Example

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

Mathematica

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

Crossrefs

Cf. A069871.

Sequence in context: A239661 A106305 A135365 * A069871 A061957 A136984

Adjacent sequences: A088874 A088875 A088876 * A088878 A088879 A088880

Keyword

base,nonn

Author

Chuck Seggelin (barkeep(AT)plastereddragon.com), Oct 20 2003

Status

approved