A235591 Numbers which on division by their digital root give quotient which is divisible by its digital root.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 18, 19, 20, 21, 24, 27, 28, 30, 36, 37, 38, 40, 42, 45, 46, 50, 54, 55, 56, 57, 60, 63, 64, 70, 72, 73, 74, 76, 80, 81, 82, 84, 90, 91, 92, 95, 100, 108, 109, 110, 111, 112, 114, 118, 120, 127, 128, 133, 136, 138, 140, 145, 146, 148, 152, 154, 162, 163, 164, 165, 168, 171, 172

Offset

1,2

Links

Table of n, a(n) for n=1..74.

Example

 108 is a term as on division by its digital root i.e. 9, gives 12, which is again divisible by its digital root i.e. 3.

Mathematica

dr[n_] := 1 + Mod[n-1, 9]; Select[Range@172, IntegerQ[q = #/dr@#] && Mod[q, dr@q] == 0 &] (* Giovanni Resta, Jan 14 2014 *)

Crossrefs

Sequence in context: A193456 A143289 A064807 * A007603 A005349 A234474

Adjacent sequences: A235588 A235589 A235590 * A235592 A235593 A235594

Keyword

nonn,base,easy

Author

Mihir Mathur, Jan 12 2014

Status

approved