A051804 Numbers with nonzero multiplicative digital root 2.

2, 12, 20, 21, 26, 34, 37, 43, 45, 54, 59, 62, 69, 73, 95, 96, 102, 112, 120, 121, 126, 134, 137, 143, 145, 154, 159, 162, 169, 173, 195, 196, 200, 201, 206, 210, 211, 216, 223, 225, 232, 239, 252, 260, 261, 268, 278, 279, 286

Offset: 1

Author

Dan Hoey, Dec 09 1999

Keywords

• nonn
• easy
• base

Links

• Index entries for 10-automatic sequences.

Crossrefs

Part of histogram of A051802.

Programs

Mathematica

nzd[n_]:=Select[IntegerDigits[n],#!=0&]; dr2Q[m_]:=NestWhile[Times@@ nzd[#]&, m,#>9&]==2; Select[Range[300],dr2Q] (* Harvey P. Dale, Jul 01 2015 *)

Formula

A051802^-1(2)